


Unexpected (a Pinecest Story)

by Edward_or_Ford



Series: Unexpected AU [1]
Category: Gravity Falls
Genre: F/M, Pregnancy, Sibling Incest, pinecest - Freeform
Language: English
Status: Completed
Published: 2016-07-14
Updated: 2016-07-22
Packaged: 2018-07-24 01:57:15
Rating: Explicit
Warnings: Underage
Chapters: 7
Words: 22,940
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7488852
Author URL: https://archiveofourown.org/users/Edward_or_Ford/pseuds/Edward_or_Ford
Summary: <blockquote class="userstuff">
              <p>Young love blossoms where it shouldn’t. What will happen when it appears that a new life has been formed from this love?</p>
            </blockquote>





	1. Part 1 - Infatuation

**Author's Note:**

> We aren’t just dealing with sibling incest here. Taking place over a period of several years, this story involves underage Pinecest, with pregnancy thrown in for good measure. If you will find it disturbing to read about fifteen-year-old siblings, dealing with the possibility of getting ready for a baby, please do not read this!
> 
> Despite the circumstances, this is above all a story of love, and how a young couple in an incredibly difficult situation deals with their love. I hope the characterisations are reflective of Dipper and Mabel, and that the emotions ring true.

## Spring 2012

Dipper wiped his brow. Spring cleaning was hard work!

The Pines family was engaged in that age-old practice of getting rid of things they no longer needed. Seemingly every year, new “stuff” would accumulate, meaning there were older belongings that probably didn’t need to be kept. On this Saturday in April, it was the basement that needed to be tackled.

They had sorted through enough old things that had been deemed expendable, including a couple of small pieces of furniture, that it would take more than one trip in the family car to haul it away to the donation depot. Dipper’s twin sister Mabel beat him to the punch when their father asked for a volunteer to go with him to deliver the first load, so this left him at home with his mom. While she started preparations for dinner, she asked Dipper to go back to the basement to sort through one last box before the others got back.

He sulked at the added work. This wasn’t fair! He was twelve years old, and it seemed lately that he had more responsibility than Mabel. He grumbled to himself as he descended the stairs. Dipper's task was to go through the family's box of old VHS tapes of cartoon movies that the twins never watched any longer. He was to make sure there weren’t any irreplaceable home videos mixed in.

After wrestling the box loose from where it was stuck in the corner and dragging it to where he had more space, he pried open the lid and sighed at the stacks of tape boxes. One by one, he took them out to examine the titles, and to make sure the tape inside matched the box. Sure enough, they all seemed to be old Disney movies, Nick Jr. television series, and other kid’s programming. None ot these had been watched by either of the twins in years, either from lack of interest or because they’d been replaced with DVDs.

There were only about a dozen or so tapes left when Dipper noticed the bottom row of tapes were not in plastic hinged boxes like the rest, but instead were in standard cardboard sleeves. He examined the titles: “Risky Business”, “48 Hrs”, “Ferris Bueller's Day Off”, “Raging Bull”, “The Shining” … Dipper didn't recognize any of these. Someone had obviously shoved some old collection of less kid-friendly movies into the box. He thought his parents might think them worth saving, and he started gathering them into a separate pile to bring up and show his mother.

Then he picked up the last tape in the row of old films, and looked at the title: “The Blue Lagoon”. He’d never heard of this one any more than the others, but he was certainly intrigued by the cover art on the box: a photo of a young teenage boy and girl holding each other close, and both appeared to be wearing nothing more than tiny loincloths. The girl’s breasts were covered only by her hair. Dipper was feeling the familiar funny tingling in his groin he would experience anytime he saw sexual stuff on the Internet he knew he wasn’t supposed to see.

After finishing the last of the tapes and verifying there were no home movies among them, he began stacking the children's tapes back into the box for giveaway. Then he stopped, and glanced nervously at the staircase. Very quickly, Dipper emptied the box again and put the old grown-up movies back in the bottom of the box, where they would stay hidden. All except one tape. The cartoons and kids programming went into the box next, and he closed the lid.

With “The Blue Lagoon” tucked under his armpit, Dipper ascended the stairs to the main level, calling out to his mother that the box was too heavy to lift. When she replied from the kitchen to leave it for now, he swiftly dashed up to the 2nd story and to his bedroom. Carefully, he hid the tape in a dresser drawer with his clothes. Closing the drawer again, he determined to wait for an opportunity to see what was up with the curious-looking movie.

* * *

 

By the time the school year ended two months later, Dipper had been left alone in the house for any appreciable length of time on just three occasions. The movie was watched, not coincidentally, three times in that span.

The boy's immature hormones stirred with each viewing of the movie. The story was of two children, young cousins, tragically stranded alone on an idyllic tropical island. It started showing the cousins as prepubescent kids, but the majority of the film portrayed the kids as teenagers after several years had passed. There was little left to the viewer’s imagination as the kids were shown falling in love, discovering sex, and even having a baby together! The young actors rarely wore more than tiny garments around their waists, and often they were completely naked. Dipper was amazed that such a movie could be allowed to be made, but he certainly wasn't complaining.

The movie did more than cause arousal, making Dipper have an erection. In his imagination, he also couldn't help substituting himself and his sister into the roles of Richard and Emmaline. The dynamic of the characters was familiar: they were playmates and friends, they helped and cared for each other, and they got into disagreements and fights: all of this was just like Mabel and himself. They had a very close sibling relationship already, but Dipper felt strange about the idea, if he and Mabel were the ones stranded alone, that he could kiss his sister. Or that he could make love to her. Or that they could have a baby together! He knew it was a weird daydream, and he was ashamed of thinking about Mabel like that. But every day, and most nights, Dipper continued to dream of living like that with his twin.

Just a couple of days into summer vacation, his fourth opportunity came. His parents left for the outdoors equipment store, but didn't tell him what they were shopping for. Mabel had already gone out to play with neighborhood friends. As soon as the car had left the driveway, Dipper dashed upstairs to retrieve the tape from its hiding spot.

After putting the tape into the living room VCR, he ran back to the couch. He had left the tape queued up to the beginning of the scene where the cousins go skinny dipping together, which would lead to the part where they made love for the first time. He was enraptured, his penis already hard in his shorts, as he watched.

Then without warning, Mabel bounced through the front door. “Diiiiiiiip! I’m borrrrrrrrrrred! Everyone’s gone to do other stuff!” She turned to close the door quickly before Mittens, the family’s notoriously moody cat, could escape outdoors.

Dipper mashed the “stop” button on the remote, then launched himself to the VCR to hit eject. The machine made strained mechanical noises at it prepared to return the tape, a process seemingly requiring several hours, from the panicked boy’s perspective. By the time Mabel stepped around the corner carrying the cat, Dipper had the tape in front of his crotch, trying to appear inconspicuous, and the television was glowing bright blue.

“Whatcha watching? Some nerd thing?” Mabel asked with a bright smile.

“Uh! Uh … it’s nothing!” stammered Dipper as he turned off the TV and stepped around his sister, heading for the stairs.

“Oh! Oh! It’s … it’s nothing!!!” Mabel mocked happily in her brazen yet somehow charming style. “Come on, Bro! Show me!” she called out to him while she struggled to hold the squirming feline.

Dipper was already starting up the stairs. “It’s really nothing important, Mabel! It’s a … a documentary! It’s like a science documentary on … biology!” he shouted as he disappeared into the upstairs hallway.

“Borrrrrrring!” Mabel groused again loudly, gently dropping the cat down on the floor. “I never thought I’d wish we were still in school! Is it going to be like this all summer?” Dipper came back down the stairs, his old PlayStation Portable in hand. “Let’s _do_ something, Dipper! Your dear sister’s _dying_ here! It’s like we’re stuck on a desert island!” The handheld slipped from Dipper’s hands and clattered to the floor. “Hah! Butterfingers!” commented Mabel with a grin full of braces.

“Yeah …” replied Dipper, flustered. He picked up the game and looked around, wanting to redirect Mabel’s attention somewhere else. “Okay, how about … a race? You try to … get Mittens to purr before I finish a lap of Sonoma on Gran Turismo?”

Mabel scratched her chin in an exaggerated manner. “Hmm! My irresistible charms on the grumpy Mittens McMittenFace, versus your girly-gaming skills. Okay, you’re on!” She ran to pick up the cat, carrying it back to where Dipper stood, his thumbs ready. Mabel calmly started rubbing and stroking the big fuzzy cat, making little cooing sounds. Dipper shifted, looking for the signal to begin. A small evil smile broke on her face. “You waiting for something, brother?” she asked slyly as she continued petting the squirming Mittens.

“Agh! No fair!” Dipper cried out laughing, launching his Corvette from the starting line. As he drove around the twisty circuit on his game console, he also thought about how happy he was with how well he and Mabel got along. She really was a perfect sister: fun, adventurous, always had his back, and was never malicious in her teasing. He really liked being with her, and couldn’t imagine growing up without her. Weird fantasies or no weird fantasies. Not that he still wouldn’t thoroughly enjoy beating her at this little contest, he thought, as he braked hard for Turn 7 and aimed to navigate around the tricky corner.

Their parents came through the front door, loaded down with bags and bulky packages. “All right, kids, listen up! Big news!” called their father. Dipper and Mabel muttered replies distractedly.

Seconds later, their mother was taking Mittens from Mabel’s arms, while their father snatched the PSP from Dipper. Then brand new bags and packs were dropped in their arms, a new cap was plopped on Dipper’s head, and just for fun, a small dollop of sunscreen was smeared on their noses. Both of them looked up to their parents in confusion.

“You’re going to have a big adventure,” their mother told them. “You’re going up north to Oregon to spend the summer with your Great Uncle Stanford!”

The twins looked at each other uncertainly.

* * *

 

## Autumn 2012

Mabel tried to immerse herself in knitting her new sweater. But she just wasn’t into it. She set her knitting needles aside and flopped back onto her back, allowing Waddles to nuzzle up to her from his position on much of the rest of the bed.

It had been one heckity-heck of a summer! She and Dipper had, over less than three months, been through an incredible series of amazing and terrifying adventures. A far cry from her initial desire for an epic summer romance, which seemed like such a _small_ thing now. Instead, she’d gotten to know and love not just one, but _two_ fantastic great uncles, made life-long friendships, seen incredible supernatural phenomena, and helped win a battle with an actual evil demon!

But every day that passed, since they arrived home in Piedmont a week prior, made the memories of what happened seem more and more unbelievable. No more quirky townsfolk, no more crazy creatures, no more magic. Just the same old school, dull friends, bland suburbia. Everything special was gone!

Well, not _everything_. Most special of all, she at least still had Dipper! The summer had cemented her bond with her closest compatriot and best bro ever. She could never forget how much of a part of summer Dipper had been with her. She’d always treasured how great he was, for as long as she could remember, but this summer had seen him become so much more! He was stronger, braver, cleverer, and more adorkable than ever.

It really scared her when she thought he’d be staying with Grunkle Ford after the summer, that she’d have to go back to her old life _alone_ , trying to grow up without him. She had found the bubble Bill had made for her to be a perfect way to just deny her heartache over feeling so abandoned. But when Dipper had told her he had changed his mind, that he wanted them to grow up together after all, the relief and happiness she felt was immense.

And she felt more than that, she recalled. When Dipper had testified at his “trial” that he wanted to stay by her side, he had punctuated the point with the same “Yes. Definitely. Absolutely!” that she had used at the beginning of the summer when she wanted to find a summer boyfriend. The connection made her heart do that flittery-fluttery thing that happened when she had thought of potential romance. She realized Dipper would be perfect boyfriend material, were it not for the fact he was her brother. Mabel found, to her surprise, that she felt more saddened than disgusted by the thought.

All this made it really hard to get back into the old routine, though! Come on, _schoolwork_? After all that she’d seen and learned? And even worse, now it was the weekend, and there was even less to occupy herself with. Even Dipper had gone for the day with their Dad to San Francisco on an errand.

What would Dipper do if he was bored like this, she wondered to herself? Probably read yet another dumb nerd book, she answered. There’s never a lack of books! Dipper should _never_ get bored!

But what the heck, she finally considered. There’s gotta be books in this house that aren’t terrible. _Mom had used to read novels all the time,_ she thought. _I should read one of hers_. Mabel wandered out to the backyard where she found her mother watering flowers, and asked if it was okay to try reading one of her paperbacks.

Her mother turned off the hose. “Hmm, I got rid of most of my books, but I’ve still got one shelf of old novels. They’re on the bottom of the bookcase in the study. Have a look there.”

“OK thanks Mom,” Mabel replied. Returning to the house, she found the shelf in question. There were two rows of books. She randomly picked a couple, but none of them grabbed her interest. Most of the novels were random single edition books by different authors. Then she noticed a row of similar-styled books, all written by the same author: V. C. Andrews. Curious, she pulled out the first in the line and read the title. “Flowers in the Attic,” she mumbled aloud, thinking about the attic that had been her home all summer.

She flipped the book over and read the back cover synopsis. Her eyes widened as she saw that it was a story about four siblings locked in the attic of a mansion, with no one they could depend on but each other. The last two sentences took her breath away: “Chris and Cathy become all things to the twins and to each other. They cling to their love as their only hope, their only strength -- a love that is almost stronger than death.”

Mabel immediately thought of how if she were in this story, she could never have a better companion and protector than Dipper. The book was building these siblings up to be needing each other to handle a really hard challenge. Well, she and Dip had faced pretty darned challenging stuff, too! How would these siblings compare to the Mystery Twins, she wondered?

Sauntering back up to her room with the book in hand, Mabel hoped she had beat boredom, at least for a little while.

* * *

 

Emotional upheaval during adolescence is nothing new for thirteen-year-olds. But due to the unique events they'd experienced together, the Pines twins were feeling the effects of new hormones in a way most young teenagers would never have to.

Mabel had read a great many romance novels before, but none that had ever affected her anything like the V. C. Andrews books had. Mabel consumed all the novels on the shelf as quickly as she could, but it was the first series, “Flowers in the Attic” and its sequels, that impacted her the most. The story focused on a brother and sister who came to fall in love as they coped with terrible abuse towards them and their younger siblings at the hands of their family. Although there were all kinds of issues with their relationship, there was something so pure about the love that Chris and Cathy shared, something so _right._ Something _perfect_! Something that was just like the way she felt about Dipper, and how she _knew_ Dipper felt about her. By the end of the second novel in the series, it had shown how that kind of love could become more, could become romantic, passionate, and unbridled. That their love could be physical. That they could be complete, together! One of these books was in her hand late at night, barely a week after she’d found the novels, when she envisioned herself and Dipper holding themselves tightly together, keeping each other strong and safe from the dark forces of the world. Their clothes would fall away and their embrace, their bond, would be even closer. She caressed and rubbed herself as she imagined her brother sliding inside her, moving lovingly within her, knowing that was where he belonged. She gasped in desperate need, thrusting a finger in and out to tickle that special spot and augment the stimulation she gave her clitoris, finally experiencing the release of the first orgasm of her life. She’d had countless more since, and every one was with Dipper first and foremost in her mind.

At the same time, Dipper had to deal with his own longing for his sister. Their adventures of the summer in Gravity Falls had been amazing, and after it was all over, he shuddered to think of all the things that had happened. Putting aside the supernatural weirdness and his hero-worship of his Great Uncles, that fact that he’d shared those thrilling months with Mabel stood out most of all. Sure, he’d been stupid every now and then: he still didn’t believe he actually considered staying behind to be some kind of apprentice, and thank god he realized what a mistake that would have been. What he remembered most were the times Mabel was hurt or in danger, when he _had_ to protect her. After losing her for days to Bill's bubble at the end of the summer, he finally knew he would do anything, _anything_ at all, to get her back. He would sacrifice everything for her safety and happiness! He knew this was far beyond what he had ever felt for Wendy. Where he had merely wanted Wendy, he _needed_ Mabel! In his bedroom, about a month after starting school, he was overwhelmed with these intense thoughts, compelling him to give vigorous attention to his penis. He flexed his pelvis and stroked himself faster and harder than he ever had before, imagining in his mind that he and Mabel were in the Blue Lagoon, naked together, passionately making love on the beach. He would never forget the incredible sensation as he climaxed for the first time in his life and ejaculated all over himself and his sheets.

As much as they both knew their feelings were forbidden and should have made them feel gross, they couldn’t help it. Neither could gather the courage to admit it to their twin, and barely wanted to admit it even to themselves, but Dipper and Mabel had completely fallen in love with each other.

* * *

 


	2. Part 2 - Obsession

## Spring 2013

Dipper and Mabel continued their final year of middle school, closing in on completing the eighth grade, preparing for the transition to Piedmont High School. Dipper was at or near the top of most of his subjects, and Mabel was a solid student who was president of the Spirit Club. As spring set in and graduation was approaching, the school year had been completely successful for the Pines twins so far.

Outwardly, at least. Inside, that was a different story.

Their secret feelings for one another had continued to grow. But they still had to keep up the appearance of normalcy. Even though they both ached inside because of their longings, they were resigned to never being able to act on them. Somehow, they both had to suppress their thoughts, which they believed to be depraved, and deal with the fact that life would have to go on. School assignments and extracurricular activities helped, so as much as possible they buried themselves in their work.

* * *

 

“We’re going back to Oregon this summer?” Mabel asked. “Why?”

Dipper agreed. “Yeah, we thought Grunkle Stan and Great Uncle Ford wouldn’t even _be_ there!”

Their father confirmed Dipper’s statement with a nod. “That’s true, kids. Your grunkles left last week for the far North, and summer is the only time the sea ice breaks up enough for them to go. They won’t be back until mid September.”

“But today while you were at school, we talked on the phone with your friend Soos,” their mother continued. “He asked if the two of you could go up again this summer. You could work for him and his fiance at the Mystery Shack, earn yourself some spending money, and have fun. Same as last summer!”

Dipper and Mabel exchanged looks. They had never relayed most of the stranger events of the last summer to their parents, particularly those that Mayor Cutebiker had decreed to be part of “Never Mind All That.” The twins sure hoped that another summer wouldn’t bring more of the same weirdness, for they had barely gotten out alive.

Also running through their heads was the sleeping arrangements. They knew that Soos and Melody had converted Ford’s old room into their bedroom, and Soos’ Abuelita had moved into the bedroom that had been Stan’s. That meant that Dipper and Mabel would be sharing the attic again. The idea thrilled and scared them, but they couldn’t let the other know anything about those emotions.

Regardless, the decision was made for them. Dipper and Mabel’s middle school graduation would take place at the end of the week, and then they would board a bus the day after that. They had to be prepared for another summer in Gravity Falls, whether they thought they were ready for it or not.

* * *

 

## Summer 2013

Gravity Falls would always be a bit of a strange place. After all, there were gnomes, manotaurs, unicorns, and any other number of weird creatures that lived in the woods near the Mystery Shack. But with the defeat of Bill at the end of his Weirdmaggedon, much of the town’s danger had disappeared.

And of course their great uncles were not around. Grunkle Stan had been such a huge part of their summer the last year, and Grunkle Ford, quirky as he was, also had been beloved. But they were off on their own adventure.

Plus their other friends in town weren’t around. Pacifica had responsibilities at home, learning the ropes of honest capitalism along with her father. Candy and her family had moved away, and Grenda had been taken on a summer-long trip to Austria with her parents by her boyfriend. And their older friends, including Wendy, were largely busy with summer jobs.

With the help of Melody and the support of his grandmother always nearby, Soos became a quite capable businessman. Tours through the exhibits were orderly and entertaining, and the Mystery Shack became a well-oiled enterprise. Dipper and Mabel had regular hours of work, predictable days off, and were paid fairly for their labour.

Coupled with having seen so many unfathomable things the year before, the returning Pines twins found their second summer vacation in Gravity Falls to be … boring! All the spontaneity and adventure was missing.

As a result of this, the twins didn’t have any distraction from each other, and their uncomfortable secrets they kept from one another.

* * *

 

“We’re the place where the ducks roar, and the bears quack!” proclaimed Soos loudly. “Congrats, Dudes! You survived the Mystery Shack!” He smiled proudly as the large group of tourists laughed at the charming Mr. Mystery’s rhyme. Soos had just completed his usual great job of being a guide to the Shack’s attractions. The visitors started filing out the door, with a few finishing up their purchases of souvenir trinkets. He followed them out, chatting up the customers, knowing that they would tell others of how wonderful their host had been while visiting the quirky tourist trap. Melody winked at him, and Soos returned a happy thumbs-up.

Melody finished straightening up a rack of postcards, then patted Dipper on the shoulder as he swept the floor. “You alright, Dipper?” she asked kindly. “You look a little tired.”

Dipper nodded as he continued his work. “Yeah, yesterday was a long day,” he replied. “I'll be okay.”

“Sorry to have to put you to work so soon, but we’re in for a busy day today.” Melody sidled up to Mabel as Soos was outside waving goodbye to the group as they were queueing to get on their tour coach. “Nicely done on the cash register, Mabel,” she said admiringly. “You just got off the bus yesterday. First day back and you’re in the swing of things quickly!”

“Pfft! You didn't see me last summer!” she joked. “I'm still scraping nine months of rust off these fingers! Wait’ll you see me in another couple of days!” Mabel made a silly grin as she flexed her fingers dramatically.

Melody laughed with delight. “Does your sister ever turn off the goofy attitude?” she asked Dipper, who was sweeping the floor.

“Nope,” Dipper smiled fondly. “I haven't found the off switch yet.” Mabel blew a good-natured raspberry towards him.

“Soooo …” Melody said, glancing at Mabel knowingly, “I remember you being Soos’ dating coach last year. You did a _great_ job! Are you … taking your own advice these days? How's that search for romance coming?”

Mabel couldn't exactly say she had already found the boy of her dreams, and that he was a few feet away holding a broom. But she also knew that she was a horrible liar, and if she tried to say there was no one, it would be an obvious fib.

“Well, there … _is_ someone I like,” she replied, feeling her face flush. From the corner of her eye she saw Dipper turn towards her. She quickly turned back to Melody, forcing a grin on her face.

“Oh, ho!” Melody exclaimed. “A boy at your school?”

Mabel shrugged, hoping Melody would drop it. “Yeah, he goes to my school.”

“Really?” inserted Dipper nonchalantly as he resumed sweeping. “I never heard about this …” He left off the next question, the one he didn't really want to know the answer to: the identity of the boy Mabel liked.

Mabel was _not_ going to volunteer that information in any case. She quickly recycled one of her lines from the previous summer. “I don't tell you everything!” she teased with a large smile.

Dipper feigned disinterest and went back to his cleaning duties while Mabel changed the subject and continued chatting amicably with Melody, this time about the relief of no longer enduring metal on her teeth.

* * *

 

In the dark of the attic that night, Dipper lay wide awake. He was exhausted, but how was he supposed to sleep?

The previous night had been his first night sleeping in the same room with Mabel since last summer. He was telling the truth to Melody: it _had_ been a long day, what with traveling by bus for 14 hours, including a transfer. Soos and Melody had their beds already made up, and they quickly went upstairs. He was able to disregard how weird this was going to feel, at least for the time being.

Dipper had fallen into a light sleep instantly, but the lack of background noise left him hyper-aware of small sounds. As a result, he woke up slightly when he heard Mabel shift her position. Facing away from her, he was about to drift back off again when he heard Mabel's breath quicken, and could barely make out a tiny rhythmic squelching noise that was in time with faint rustling of sheets.

He had instantly become aware of what Mabel was doing. He didn't think it was right to listen in, but letting Mabel know he was awake would have been even worse! Trying to keep his own breathing as quiet as possible, he had to lay still, his erection straining, as he could hear Mabel gradually work her way up to completion. It was almost painful to listen to the stifled squeak from her throat, accompanied by rapid wet rubbing noises, as she climaxed. Dipper was awake in frustrated arousal for at least an hour after that, and then had erotic dreams when he had finally fallen asleep. Horrified, he'd awakened in a sticky mess, as he'd had a powerful wet dream about Mabel. He managed to get to the shower without being noticed, but it didn't prevent him from being tremendously anxious and embarrassed.

Now it was the following night, and on top of everything else, he was jealous! Mabel's statement that there was someone at school she liked … it tore at him. This mystery boy was obviously who Mabel had been fantasizing about the previous night in the dark. The guy was so lucky! What he wouldn't do for Mabel to feel that way about _him_ , instead! Dipper wanted to be the one making her feel loved and special, making her feel pleasure. For _his_ fingers to be running over her skin, then probing her mysterious nether regions for her. _He_ wanted her to feel his urgent kisses on her lips, and his tongue and gentle lips on her breasts. _He_ wanted her to feel him pushing himself into her, make her _know_ that he loved her more than anything …

Dipper couldn't take it anymore. He was as hard as he could remember, and he needed release. He listened to Mabel's deep, regular breaths, glancing over to her peaceful, relaxed face. “Mabel?” he whispered, trying to make sure she was asleep. Her light snoring continued uninterrupted.

Beneath the covers, Dipper carefully pulled his shorts down below his knees and pulled one leg out to free his movements. Then he grasped himself and very slowly began stroking, the naturally-lubricated foreskin gliding down over the uncircumcised head with each downward pull.

His breaths came a bit quicker, more labored, as he allowed his pelvis to thrust up slightly with each agonizingly slow pull. He knew he had to keep quiet. Mabel’s breathing sounded the same as before.

Dipper had never had to be this careful, had never taken this long with his masturbation sessions. The pressure built in his groin as it never had before.

Unwittingly, the pace of his movements gradually increased. He struggled mightily to keep silent, breathing in tiny shuddering gasps. He barely processed the light fapping noise he was producing as he imagined Mabel moving on top of him, his penis deep inside her, his sweaty skin pressed against hers.

Eventually Dipper began feeling the delicious tightening, and he knew his release was imminent. He squeezed and pulled even faster. Then he realized with a start that he had nothing to “catch” his semen with. In a panic he sat up, yanked off his t-shirt, and threw it around his jerking hand and penis barely in time. He winced hard as the biggest orgasm of his life hit him, and he erupted repeatedly into the shirt. A whimper escaped his mouth before a huge intake of breath. Then he was panting quickly, his body deprived of oxygen as his penis produced the last drops of his seed.

As he calmed down, he glanced over to the other bed, thankful that Mabel had not moved a muscle. It would have been the most embarrassing moment of his life if she'd known what had just happened. He wiped up the remnants of his mess with the shirt, quickly tossing it down into the gap between his bed and the sloped wall. Pulling his shorts back on, he collapsed carefully back onto his pillow.

Finally relaxed, his chest rising and falling quickly but gently, Dipper again turned his head to gaze at the beautiful, sleeping face of his sister. His heart squeezed in pain for an instant, knowing everything that he felt for Mabel was wrong, and that she could never feel the same way about him in return. A tear formed in his eye, and he quickly wiped it away. Finally, the fatigue from lack of rest and the hormones released from his orgasm combined to allow him to fall into a blissful sleep.

As soon as Dipper's snores became deep and regular, Mabel's eyes opened. Hours passed before sleep claimed her again that night.

* * *

 

Soos and Melody disappeared from sight, still waving goodbye from the side of the road as the bus rounded a corner and headed for the highway.

Mabel exhaled dramatically and flopped her head on Dipper's shoulder. “Heck of a way to celebrate our fourteenth birthday, huh Bro?” she muttered.

“Yeah, we've definitely had better,” Dipper grunted in reply. “Especially since our birthday was a Saturday this year. You’d think Mom and Dad could’ve driven up to pick us up, so we could have a nicer day instead of an all-day bus trip. Kinda spoils the fun!”

“They said they couldn’t leave Waddles alone in the house, and it’s too far to take him up and back at once,” Mabel said, defending her pet from any hint that the pig was at fault for their situation.

“Okay,” Dipper grumbled, “But it still sucks.”

“Yeah,” Mabel agreed. “I don’t even feel like playing ‘bus seat treasure hunt’.” Dipper leaned his head onto hers in sympathy, causing Mabel to tuck her chin in comfortably. It always made her feel instantly better when she could have cuddle time with her Dippy Ruxpin. “I guess all told, though, it wasn’t _that_ bad of a summer! I mean, you’re glad we came back, right?”

Dipper couldn’t stop a small smile from growing. “Yeah, I am. Maybe it wasn’t as incredible or unbelievable as last year, but it was fun! We got to kick back a lot more this summer, didn’t we?”

Mabel smirked. “Yeah, not quite as much screaming and running for our lives, huh? I think after a while, that started to wear a bit!”

They started reminiscing about the crazy events of the previous summer, laughing at the silly and happy memories, neglecting to bring up the scary and horrific ones. They also replayed some of their recent fun times of the summer just concluded.

Unmentioned were the subjects less comfortable to talk about. Things like how Mabel started noticing just how often Dipper demonstrated his cute protective tendency, while Dipper began more and more appreciating Mabel's efforts to draw him out of his shell. And like how they each noticed the way their siblings looked better in their swimsuits at the pool than the previous year. And, of course, their silent observations of each other's occasional masturbatory practices were also ignored.

They had both successfully learned to push down their secret longings for one another, and to only show the genuine sibling affection that they still felt for one another. They laughed together as they recounted the best of their memories, then started thinking about their immediate future.

“So … what about high school?” Dipper asked. “We start in a few days. You ready for it?” Dipper's voice became more tentative.

“Nope!” Mabel replied immediately, then a little quieter, “but I guess we gotta, huh?”

“Yeah,” Dipper said grudgingly. “Back to the bottom of the totem pole. I’m not scared of the work or anything, but I know what it’s going to be like. You know … nerds don’t exactly get an easy ride.”

“Dipper, you’re the _best_ kind of nerd,” Mabel shot back. “You’ll be so busy leading the math geeks team, and your dumb DD &MD club, and whatever else you wanna do, you’re gonna _run_ the school. You’ll do fine!” She punched Dipper lightly on the shoulder, drawing a half smile from her brother. Then she slouched and put her head down. “It’s _me_ who’s not gonna fit in!” she said with a frown.

Dipper scrunched up his face in confusion. “Wait what? Why do you think that?”

“Come on, Dip! You know I’m still just a goofy little kid! I’m not _close_ to cool enough to fit in at high school, not the way my weird brain works, man!” Mabel turned her head to peer up at Dipper. “I mean … I _like_ being silly, you know that!” she said with a brave smile. “And that’s fine for middle school, I guess, but … there’s going to be _seventeen-_ and _eighteen_ -year-olds there! It’s no place for a little freak show like me!”

Dipper nudged her shoulder with a grin. “Mabel, they'll be _lining up_ to be part of your freak show, I _guarantee_ it! I know _I'll_ be buying a ticket!” Mabel nudged back half-heartedly, but Dipper could tell that she was still unconvinced. “Seriously Mabes. Square pegs in round holes: that's us! We'll help each other through. We always have!” Then it was Dipper's turn to twist his head away slightly. “Unless … you don't _want_ me to hang around with you anymore …”

Mabel looked astonished. “Dipper … who said I don't want you with me? I never said that!”

“Well … well not exactly, but …” he stammered, suddenly feeling the urge to scratch the back of his head. “You … you said … back when we first came up here a couple of months ago, you told Melody there was a guy at school you really ... _liked_ … and I just figured you’d … I don't know, you'd want to try to be with this guy or something ...”

Mabel remembered the conversation, and hadn't realized it bothered Dipper so much. She'd been trying to cover up that Dipper had been the guy she liked, but instead made him feel abandoned. And he had nursed that feeling all summer! The poor goober! “Oh, poop, Dipper!” Mabel said warmly. “How could I want to be with some other guy when I’ve got you!”

Dipper turned back and looked at Mabel strangely, and she realized how that sentence had sounded. It sounded altogether too much like the truth!

“I mean, hah hah, I was just _joking_ with Melody about there being someone! You know … didn’t want her to think I’m a flop at the old game of love, am I right?” Mabel proclaimed, grinning. “And of _course_ I want to hang out with you!” she added.

“Yeah, okay,” Dipper replied after a moment. He paused again, clearly trying to make up his mind about something. Then he blinked twice and took a breath before continuing.

“I _always_ want to hang out with you, Mabel,” he said quickly, a tiny catch in his voice.

Mabel blinked in return, her nervous grin frozen on her face for an instant, then it melted into a genuine, affectionate smile. “Dawwwww …” she cried quietly. “I need a big one of those awkward hug thingies!” She pushed her arm around his back and leaned over to squeeze her brother, her cheek pressed against the front of his shirt.

Dipper returned the hug tentatively for a few seconds, then more tightly and comfortably as his jaw rested on Mabel’s head. They held the embrace for a long moment.

“Happy Birthday, Bro Bro,” Mabel murmured into Dipper’s chest.

“Happy Birthday, Sis” Dipper replied softly, his lips lightly brushing the top of her head.

With a quick “Pat! Pat!” and a fond chuckle, they released one another reluctantly, then rested their weight against one another again to get comfortable for the hours of bus travel to come.

* * *

 


	3. Part 3 - Revelation

## Autumn 2013

“Help me set this up, Dipper!” Mabel demanded cheerfully, flopping forward onto Dipper’s bed while holding her new laptop, an early Christmas gift from their parents a few days before.

Dipper was bouncing lightly from the impact of Mabel’s weight on his mattress, and glanced up with a small smirk from beside her on his bed. He was sitting up with his back against the headboard, reading a novel. “Once again, you need the assistance of the resident computer geek, huh? Maybe you need to pay for a support contract?”

“Aw, you _have_ to help me, Dip!” Mabel shot back in a fake whine. She rolled over towards him onto her back, her head coming to rest in his lap. Her upside-down face gazed pleadingly up into Dipper’s, eyes huge and bottom lip thrust out pathetically.

The smirk on Dipper’s face widened and he rolled his eyes. “Hopeless!” he taunted.

“As hopeless as you when you had a rip in the crotch of your pants last week, and you needed me to sew it up?” she replied sweetly.

Dipper closed his eyes in mock resignation and set his book aside. “All right!” he huffed.

Mabel squealed and flipped over, wrapping her arms around Dipper’s waist and squeezing, while Dipper rested his arm across her shoulders and affectionately stroked her hair with his other hand. She happily tilted her head up to look at his face, and he smiled back at her.

For the last few months, the twins’ close bond had grown even closer. To an outside observer, the playful banter and close physical contact between them could have looked almost flirtatious, and in a way it was. The love and attraction both twins felt for the other was stronger than ever, but they tempered their actions just enough that their un-sibling-like feelings weren’t blatantly obvious to see. They just came across as oddly close. Individually, they enjoyed thinking about being more than brother and sister to each other, unintentionally managing to make each other feel very desirable and aroused.

On the same wavelength, they both broke the embrace at the exact moment they thought it might be getting too weird for the other. “So, what’s wrong?” Dipper asked, now fairly well practiced in the flow of their evolving relationship dynamic.

Mabel also pulled herself back together smoothly. “Dad says I can use this ‘HBO GO’ thing on my laptop. So I can, you know, call up whatever I want, instead of just … whatever’s on!” Dipper snorted at Mabel’s terminology, resulting in Mabel lightly punching Dipper in the stomach. Quickly Dipper had the settings configured, then sat back with his book as Mabel started scrolling through the back catalog of TV shows and movies that were available.

“Man, there’s some stuff on here that lil ‘ol innocent me shouldn’t be watching!” Mabel giggled.

Dipper perked up at that. “Like what?”

Mabel gestured at the screen. “Like ‘Game of Thrones’, for starters! From what I’ve heard, it should be called ‘Blood and Boobs!’ Have you ever heard what it’s about?”

“No,” Dipper lied. He actually knew _exactly_ what it was about, and in fact had secretly read all of the “Song of Ice and Fire” novels the show was based on. “How did _you_ hear about what the show is like?”

“Wendy told me a bit about it our first summer up north, but I really don’t know very much about the story. She and her crew would sometimes watch it at Thompson’s place,” Mabel replied. Her expression turned sneaky. “Wanna watch an episode now?”

Dipper was torn. He was curious to see if the television adaptation was as good as everyone said it was. But he had to be careful. They couldn’t get caught by their parents watching this, and he’d also have to keep up the lie to Mabel that he didn’t know anything about it. In addition, he was very aware of two characters in the books named Jamie and Cersei Lannister, a pair of twins. Seeing how they would be depicted, while watching with Mabel beside him, could be exciting, or really mortifying.

He decided to take a chance. “OK, do it. I’m making sure Mom or Dad don’t see,” he said as he got up to close his bedroom door.

Mabel started the first episode of the first season, the twins watching on the laptop while lying on their stomachs side by side on the bed. Sure enough, there was plenty of graphic gore and gratuitous nudity. Dipper squirmed with embarrassment at watching this with Mabel, but he didn’t want to stop either.

As the episode drew to a close, the character Bran was overhearing sounds of passion through an open window, and Dipper knew what was coming. Sure enough, the Lannister twins were revealed as the source of the noises, with Jaime taking his sister from behind

“ _And THERE’S the incest!_ ” Mabel cried with mischief.

Dipper jumped, gaping at Mabel in disbelief as she paused the playback. “Oh come on, Dipper! _Everyone_ knows the twins on this show are gettin it on!” she teased. “And so did _you!_ I’ve seen those paperbacks under your bed! You knew _exactly_ what was going to happen!”

“Sorry,” Dipper said sheepishly, blushing. “But it’s a little … weird, I guess.”

Mabel’s cheeks also darkened. “I think we can handle a little weird,” Mabel replied, and Dipper swore her eyes twinkled. He returned the expression without thinking.

With that, Mabel grinned and unpaused the video. The show quickly concluded, and without hesitation they decided to call up the next episode.

* * *

 

## Winter 2014

The twins and their parents got off the elevator in the lobby of the beach-front hotel. The kids were in bathing suits, their parents were dressed in comfortable shirts and shorts.

“You have your keycard?” their mother said to Mabel. She grinned and waggled her shoulder bag that also contained her towel and suntan lotion. She bumped it playfully into Dipper’s matching bag. “Good. Your father and I are going to check out the casino further down the strip. You two go enjoy yourselves in the pool and on the beach, but make sure you both leave time to go back up to your room and change before dinner.”

The Pines family didn’t often splurge, but it had been a busy and successful year for both of the twins’ parents. They decided the family could enjoy a trip south to a Caribbean island resort for March break. It was a great surprise for their children, who had never in their fourteen years been on a tropical vacation.

Dipper and Mabel immediately headed outside to the hotel’s pool. The heat of the sun and the cool of the water combined for a comfortable and pleasant early afternoon as they played on the waterslides and splashed each other in the deep end.

It was a great opportunity for Dipper to admire Mabel’s body. The one-piece suit she wore wasn’t tremendously revealing, but it did nothing to hide her developing curves. Dipper dove underwater often to get a clear, unobstructed view, and really wanted to be able to slide his hands along her small but feminine breasts, hips, and behind. Thankfully, the temperature of the water was low enough that his penis didn’t advertise his admiration too noticeably.

But soon enough, they agreed that they had experienced as much fun as could be had in the pool. “ _To the beach!_ ” Mabel screeched, sending one last splash of water at her brother before swimming quickly for the ladder. Dipper followed, happily taking in the view of her backside as she pulled herself out.

As they walked to the ocean across the beautiful sand beach, Mabel continued her own subtle appraisal of Dipper’s maturing physique. He was still skinny, but muscle definition was also becoming noticeable in his arms, shoulders, and mostly-hairless chest. She wished his swim shorts weren’t so baggy, so that she could see if his ass was as cute as the rest of him.

They decided they wanted to see how the water was, but they had to set down their bags. Looking around, Dipper didn't see anywhere they could safely leave them unattended.

He saw a large group of at least three families with children, heading further up the beach and carrying similar bags as the twins were. In that direction, the shoreline curved out into the ocean and the sand piled up into a dune, so that the section of beach beyond was hidden from the busy area directly in front of the hotel. Ahead of the group, other beach goers were cresting the dune and disappearing from view as they descended to the other side.

“Let's see where they're going,” Dipper suggested. “There might be places to stash our bags there.”

Over the next few minutes as they strolled down the beach, the twins continued their unconscious flirting with each other, the surrounding waterfront much less important than spending time focused on each other. As they began climbing the shallow slope of the dune, they failed to pay any attention to a sign that was posted beside the path.

Mabel had just finished putting forward a funny theory on how Mermando’s family might be from around the island, when they reached the top of the small hill.

“Uh ... Mabel?” Dipper said slowly. Mabel saw that he was staring at the beach before them, and she also looked.

This section of the beach was less crowded, but there were still more than enough people for the twins to see that this was a “clothing optional” beach.

At first, both of them were hit by the urge to immediately turn around and go back: they were uncomfortable because they had never seen casual nudity before. But then they noticed that none of the people were acting strange about it. There were sunbathers and swimmers of all ages, from toddlers to seniors, all enjoying not being encumbered by swimsuits. They noticed that there were several teenagers that looked about their age, as well. No one was showing any shame, regardless of how fit, or how out of shape, they were.

Mabel looked back at Dipper carefully. “You … wanna stay here?” she asked, not sure of what she wanted to hear as a response.

Swallowing, Dipper was about to take the safe way out and turn around. Then he locked eyes with his sister, seeing that she was trusting him to decide for them.

He hoped he knew what he was doing. With a shy grin, he replied, “Sure … why not?” Mabel’s face broke into a smile that surprised both of them.

They found themselves a spot on the beach that was not too near any other people and spread their towels beside each other. For several moments, they just sat there, glancing around at each other and at the sunbathers, but not really looking. There were naked people in every direction, casually displaying body parts that the kids had never seen in real life before.

“Dip, we’re … uh … kinda the only non-nudified people here,” Mabel said quietly.

Dipper took a deep breath. “Then … let’s just do this?” he said, pulling the drawstring to his swim shorts and pushing his thumbs under the waistband.

Mabel pulled the straps of her suit down off her shoulders, holding the garment to her chest with her hands. Then she nodded. “Let’s do this!” she replied bravely.

The twins lifted their butts, pulled down their suits to their ankles and removed them, dropping the pieces of fabric beside them. Hugging their knees in front of them, they were naked in front of each other for the first time since they were probably two or three years old. After a quick awkward moment of half glances at each other’s bodies, they managed to lay down side by side on their stomachs, resting their heads on their arms and staring wide-eyed directly at each other.

“This … is … cray cray!” Mabel whispered loudly.

“Yeah!” Dipper said in a hushed voice. “... Are you all right?”

Dipper’s protective concern immediately relaxed Mabel. “Yeah, I’m good, I think.” She took a deep breath, a large smile of relief spreading on her face. “It feels … really _amazing_ to be naked out in the open!” she said as she gleefully squirmed on her towel.

“Yeah … it does!” Dipper said, starting to grin as well. He surprised himself with the truth of the statement. Dipper had always been the more self-conscious of the pair, and he could only assume it was Mabel’s presence that was driving him to so adventurous. To be naked! In _public!_ He liked the feel of the light wind and the sun, both now caressing his entire body. It was a very freeing experience.

For the first few minutes the twins just talked, slowly getting accustomed to being naked. People strolled to and fro past them, some heading to the ocean, others just enjoying a walk.

Mabel had seen enough. Actually, she _hadn't_ seen enough, at least not enough of Dipper. And taking the opportunity to let him see all of her? She wanted to do it now. It was time to get off the towels.

“C’mon, Captain Cheese Dip,” she invited, lifting herself off her elbows and up to her knees. Dipper had a perfect up-close view of the front of her body, and he gulped involuntarily. She reached to grasp his hand. “Let's go try swimming now!” She got to her feet, relieved that her brother didn't resist as she pulled him upright, as well.

Before taking a step to the water, they took a moment to appraise each other's bodies, but trying not to look too interested. Mabel thought Dipper’s “dipstick” was fascinating: he had a sparse patch of hair surrounding the base of a penis that wasn’t fully hard, but definitely wasn’t tiny, either. She couldn’t help but admire it, and how cute it was when it and the sack behind it swayed slightly with Dipper’s movements. Meanwhile, Dipper was trying and largely failing to not to stare at his sister. The tiny bounces of her breasts were wonderful, as were her perfect-looking nipples. What he could see of her crotch was mostly just a light fluff of hair with a puffy slit beneath it. She was as beautiful as he had imagined.

They didn’t even notice they hadn’t released each other’s hands. Dipper was blushing as he rubbed the back of his neck. “You … look nice, Mabel,” he mumbled bashfully.

Mabel’s blush radiated across her skin, as well. “Aw, thanks Bro. I … think you’re lookin’ pretty fine, yourself.” Their gazes met again, and each saw the same embarrassed grin that graced their own face. Mabel snorted, causing Dipper to bark a small laugh, and the ice was broken.

For the rest of the afternoon, the twins hung out, with the same odd vibe of seemingly oblivious attraction. Only now, they were nude, which ratcheted up their emotions that much higher. Every touch, every glance was more electric. As they swam and played in the ocean, hands and feet would “accidentally” glance across each other's skin. Back on the beach, they helped each other apply sunscreen where bathing suits had previously covered. Mabel confirmed that Dipper’s butt was, in fact, very cute, and she shivered as she applied the lotion for him. Everything was wonderfully exciting, quietly frustrating, and very arousing.

Dipper in particular had difficulty with the obvious physical evidence of his excitement, particularly as his earliest fantasies of him and Mabel together took place on the beach of the “Blue Lagoon.” His penis was in a “mostly erect” state all afternoon, his brain and body at war constantly over what condition he wanted to present himself to Mabel. He made several clumsy, stuttering attempts to blame his “condition” on the wind or just anatomical fickleness. Although she was mightily tempted, Mabel sensed she shouldn’t make fun of him, and gradually Dipper became more comfortable with himself being completely exposed.

As dinner hour neared, the teens reluctantly put their bathing suits back on for the walk back to the hotel. They both now agreed that the whole concept of having to wear them sucked, but such was life.

“Well I'm glad we did that!” Mabel said, wrapping her arm behind Dipper's slightly sunburned back and shoulder as they neared the hotel. “Another exciting chapter in the New Adventures of the Mystery Twins!”

“Mabel!” Dipper groaned, cringing at the thought of anyone, particularly their parents, learning that they enjoyed a nude beach together.

She laughed and poked him playfully. “And you know what? This is all _practical_ , too!” Mabel continued. “Now for the rest of our vacation, we don’t have to run into the bathroom to change our clothes. I mean, what’s the _point_ , after today?”

Dipper didn’t want to disagree with that logic, but he had an immediate need to have the bathroom all to himself: he desperately needed to relieve the uncomfortable pressure that had built in his testicles all afternoon. There was no way to explain his urgency, not without revealing that he had been so turned on by her all day, he’d literally been in pain. How would that sound? No, he couldn’t explain it to her at all.

Once in their room, he hastily grabbed his clothes and headed straight for the bathroom. He brought himself to orgasm after only a few seconds of rapid stimulation, washing away his first case of “blue balls” in a wonderful wave of satisfied bliss.

However, that relief came at a price. Mabel thought he had changed his mind about how cool it was to be so open with each other. Not wanting to push things, and feeling like she should avoid embarrassing him further, she waited until Dipper emerged from the bathroom, then she also used the privacy of the locked room to change her own clothes.

He noticed her awkward change of attitude, and knew he was the cause, but felt helpless to do anything about it. The end result was that the twins buried whatever progress they had made that day in developing their relationship. For the remainder of the vacation, they kept their distance in their hotel room, and never suggested to the other to sneak off to the nude beach again, even though privately they both wanted to.

* * *

 

## Spring 2014

Going to the prom was a stressful enough event for any student at Piedmont High. For some, it was not pleasant at all.

In general, Grade 9 freshmen were largely unattached, often still forbidden by parents from going on dates until they were older. But that didn’t stop a lot of young students from going anyways. Groups of boys and girls would gather together, occasionally asking or being asked to dance by someone from another group.

Mabel was similarly restricted from dating. She had no date to the prom, but she decided to go anyways and be with “her people”, as she referred to her small posse of oddball friends.

It seemed like she was having a good time. Because she was outgoing and was always hamming things up in classes, she enjoyed a kind of popularity at school. She certainly wasn’t one of the cool girls: instead, her upbeat attitude and always-friendly demeanor made her approachable to “normal” boys. She didn’t lack for dance partners as the night went on.

But Mabel was growing more and more upset with every moment of the prom. All around her were couples, happily enjoying the evening together. There were kids developing new feelings. And from some of the boys she danced with, she saw signs of genuine affection. Some of them kind of _liked_ her.

And Mabel was having none of these emotions herself. Not for anyone at the prom, anyways.

Dipper had stayed home, saying he wasn’t interested. Mabel had half-heartedly tried to get him to go, but secretly she was glad he didn’t. She didn’t know what she would do if she saw some other girl approach her brother and ask him to dance, or even worse, if he'd asked some other girl himself. And she’d have had to resist asking him to dance herself, because at prom, that would be very strange. But now Mabel missed Dipper. And it hurt her to realize that the boy she wanted to do all these “prom”-y things with was the boy that she couldn’t ever have that happen with. She got more and more down in the dumps as the evening went on.

Their mother had volunteered to pick up Mabel and her friends from the school, dropping them all off and finally arriving home after one in the morning.

“But you had fun, didn’t you?” the twins’ mother said as she unlocked the door and entered their home.

Mabel shrugged. “There was lots of romancin’ goin’ on, but none for me!” she griped.

Her mother tsked and squeezed her shoulder. “Oh, Pumpkin! We think you’re too young to have a boyfriend yet,” she said as they climbed the stairs to the second floor. “You’ll be ready to start dating boys in the next little while, I think. In the meantime, you shouldn’t stress about it.” She nodded to the light peeking out from beneath her brother’s bedroom door. “Dipper stayed home. He had the right idea. Looks like he’s still up. Say goodnight to him before you turn in, okay?” Her mother kissed her cheek and went into the master bedroom, closing the door behind her.

Mabel paused before she could tap on Dipper’s door. Did she _want_ to see him at that moment? Wouldn’t that just be the final stake through her chest? To see everyone else able to act on matters of the heart wasn’t enough? Dipper being her brother reinforced why she _couldn’t_ act. She’d fallen in love with someone who she could never have. To face him now was too much! She turned around, ready to just collapse onto her bed.

Dipper’s door opened as she crossed the threshold to her room. “Hey,” he said quietly. “I thought I heard you co- ….” His voice trailed off as Mabel went into her room without turning around, and starting closing her door. Dipper leapt forward and held it with his hand. “Mabel, what’s wrong?” he asked, concern evident in his tone.

“Nothing, Dip,” she grumbled. Still, she allowed Dipper to follow her in.

He carefully closed the door behind him. “Mabel, it’s not nothing,” he said. “You didn’t have a good time at the prom?”

Mabel sat on her bed and flopped unceremoniously onto her back. The frilly spaghetti-strap prom dress splayed out, much as her arms did, as she stared at the ceiling. “Using those mad investigation skills to figure that out ... Inspector … Dip-adget?”

A tiny smile crossed Dipper’s mouth. “That was the _worst_ play on words I’ve ever heard from you.” Then his face turned sympathetic as he sat down beside Mabel on her bed. “Now I _know_ you didn’t have much of an evening. C’mon Mabes!” He reached over half-heartedly to tickle her kneecaps. “Out with it.”

Mabel was in too fragile a state to play her usual “affection game” with Dipper: she was afraid her true feelings would spill out, She batted away his fingers, then covered her face with her hands. “I can’t, Dipperrrrrrrr,” she groaned.

She heard Dipper’s voice harden. “Did something happen at the dance?” he asked. “Did someone do something to you? I’ll-”

“No, Dip,” she interrupted, “nothing happened.” His protectiveness, the way he cared about her, made her love him more than ever. Why did he have to be her _brother?_ Why couldn’t he be someone who could feel the same way for her that she felt for him? “I’m just … it’s me! I’m too … _weird_ for all this romance-y … prom-y ...  poop!” she mumbled through her palms on her face.

“Yeah,” Dipper replied solemnly. “I know how _that_ feels.”

The tone of his voice poked a hole in Mabel’s shield of self pity. She dropped her arms and looked up to Dipper, who was just staring at his ankles as he sat beside her. He looked just as down as she felt. She kicked herself for not seeing it, for giving in to her old selfish tendencies. Regardless of her own down-in-the-dumpiness, and that he was the reason for her mood, it wasn’t his fault. Her broski looked like he needed some old-fashioned TLC, and darnit, she would buck up and give it to him!

Mabel sat back up and turned towards Dipper. “C’mere,” she said as she wrapped her arms around him. “Dippin Dots needs hugs!” She pulled him close and nuzzled her head into his neck, inwardly knowing she wanted this just as much as she thought Dipper needed it.

She sighed happily when Dipper didn’t hesitate at all. He immediately returned the hug and rested his cheek against Mabel’s ear.

There was a long moment that neither twin moved. Mabel wasn’t even sure how much time had passed. She only knew that she was more at peace than she had been for a long while. Without thinking, she twisted her position to get more comfortable, pressing her breasts into Dipper’s chest as she reapplied her squeeze.

For a split second, Mabel feared Dipper would freak out at this. But instead, he also shifted to accommodate, burrowing his face into her hair. They were sharing the most snug, intimate embrace she had ever experienced.

Everything Mabel had been feeling for two years, all the pressure she felt on her heart from the prom, overflowed in that moment. She couldn’t stop it, and she didn’t want to stop it. She had to let out what she desperately wanted to say.

“I love you Dip,” she whispered.

She felt his muscles tense, and instantly Mabel feared the worst. He was creeped out! He was disgusted! For what seemed like forever, they were frozen in the hug. She opened her mouth to explain away the words, to say that she didn’t mean it _that_ way, when she heard Dipper’s tentative whisper in reply, “I … love you too!”

Mabel felt Dipper take an uneven intake of breath. Slowly she pulled her head back so she could see his face. The instant she saw the look of fearful longing, the quivering lower lip, the wide, moist eyes … the moment he released a shuddering sigh ... all doubt was gone. Though their mouths were only an inch apart, Mabel wanted to dive forward, lest the moment slip away.

And she was delighted when Dipper beat her to the punch. He leaned in and kissed his sister for the first time, a kiss that she returned passionately.

* * *

 


	4. Part 4 - Consummation

* * *

## Summer 2014

“So … here we are!” Dipper said nervously after closing the attic door.

Mabel stood close to Dipper. She twisted her hair in her fingers, a habit that gave away that she was a bit anxious. “Yup! … Right here!”

Dipper took a step forward, his right hand vigorously scratching the back of his neck. “Are y- … are _we_ sure we wanna do this?”

Touched by her brother's concern, Mabel felt her worry melt away. She took a deep, confident breath. “Yeah, Dip. I am!” She reached behind his head and held his hip in her other hand. One look into her brother’s adoring eyes, and all doubt was gone. She _wanted_ this!

Mabel smiled, attempting a seductive tone. “I … _hope_ you are, too.”

His sister’s self-assurance was exactly what Dipper needed to hear. “Yeah!” he whispered dreamily in reply, leaning his head down carefully from his slight height advantage to kiss her.

A week had passed since their first kiss. In that time, the twins had kissed many more times, and had explored and confessed their feelings to each other.

The night of the prom, they were still uncertain. They had kissed enthusiastically, but then as they clumsily laid down on Mabel's bed, the spaghetti straps on her dress snapped, exposing her breasts as the top of the dress fell down. They both awkwardly agreed that it would be best if Dipper were to return to his room, even though they had seen each other naked just a few months before. Later they would talk about how they both felt, that everything could have spiralled out of control. And with their parents just down the hall, they were likely correct shutting things down on that first, incredible night of discovery.

In the days that followed, both of them were still insecure, wondering if their twin would start feeling sick about what they were doing. Neither could be sure that their dream wouldn’t still revert into a nightmare.

They could scarcely believe it, but they came to realize the dream was true! Slowly they revealed to each other how they had felt for so long. Tears flowed as they quietly stole away brief moments together, making a connection they had denied themselves even the hope of ever happening.

However, such moments were brief, and very scarce. Final exams needed to be written the whole week following the prom, so they needed to study. Their parents were around, of course. And they had to get packed, as they were scheduled for a third summer in Gravity Falls, and they would leave the weekend immediately after exams. They barely got to second base together, and the whole time they were afraid of getting caught, and terrified to ask the other just how far they wanted to go with this new relationship.

It was on the long bus ride north that the twins finally had time to talk. They were both elated, and somewhat scared, to admit to one another that they both very much wanted to do more together. Much more. As in “all the way” more!

But if that was actually going to happen, they agreed they needed protection. They could not act foolish. At a rest stop on the bus ride, a red-faced Dipper tried to sneak nonchalantly into the washroom, where he purchased two condoms from the vending machine. He was certain that every person present in the restaurant was staring at him and judging him for what he planned to do with his sister.

Now the two of them were alone in the attic of the Mystery Shack late that same night. They knew that they wouldn’t be disturbed, since Soos said he was busy fixing a display case and Melody was occupied feeding their infant son.

Dipper had to break their kiss to pull the condoms from his pocket and drop them on the night table between their single beds. Then they quickly fumbled with buttons and zippers, all the while kissing all over their sibling’s face and neck. The pent-up desires of the past week drove them to dispose of their clothes as rapidly as possible. As they stood naked and close to one another, they looked each other up and down unabashedly.

“You're so beautiful,” Dipper whispered, tentatively running his hand through Mabel’s long hair and across her shoulder, while his eyes bounced up and down between her face and her breasts.

Mabel’s breath caught as she lightly dragged the fingers of both hands down Dipper’s chest, then across his flat stomach to his waist. She gripped his skin and drew herself a half-step closer, leaving only a few inches between them. “You’re pretty handsome yourself!” she breathed in reply.

Their lips touched again, and their bare bodies came together. Mabel’s naked breasts pressed tantalizingly against the skin of her brother’s chest. Fingertips and palms first caressed shoulders, waists, and backs, then moved to hips, breasts, and butts. Dipper’s very erect penis poked between Mabel’s legs, the top of his shaft nestling its way into her folds as the twins panted unsteadily into and around each other’s mouths. Their pelvises began grinding together, seemingly of their own accord.

One of Dipper’s hands moved around from Mabel’s behind to slide between their bodies. Palm facing his sister, he reached down to explore between her legs. His middle finger found the top of her slit and he moved it down an inch, right into the wondrous hot and wet channel, and over a small bump. Mabel gasped and her eyes squeezed shut, her body clenching at Dipper. He wasn’t sure if this was a pleasant or painful reaction. “Are you okay?” he verified, supporting his sister’s body with his free hand while holding his finger immobile.

“Yeah!” Mabel breathed in reply with a nod. Dipper decided to try that bump again, and he slowly drew his finger up and back down, completely overwhelming her. “Oooooo yeeeeeaaaaaaah!!” she moaned, one hand clutching tighter behind his neck while the other reached to grasp Dipper’s penis for the first time. She had just enough brain power to command her hand to pull on it up and down next to her vagina as she rode through the wonderful stimulation on her clitoris.

Dipper tensed and groaned as well. “Oh god!” he gasped in pleasure, setting his finger to work on that magical button he’d found.

The twins fingered and stroked each other to ever-increasing levels of arousal, pressing their mouths together to stifle the passionate noises they were making. It didn’t take long before Dipper’s whimpers grew louder and higher pitched as Mabel’s pants and gasps became deeper and throatier. Finally, Dipper winced hard, an almost pained expression on his face, and Mabel felt his penis throbbing as warm semen splashed on her thighs. An enormous orgasm of her own took hold, Dipper doing his best to hold her as they both rode out their intense first sexual moment together.

Basking in the afterglow, they moaned quietly and gently continued kissing as they came down from their fervent high. When their lips finally parted, Mabel’s eyes fluttered open to find Dipper staring dreamily at her in loving amazement.

“Wow!” he said in a low voice, a small smile spreading on his blissful face.

Mabel thought he looked adorable. She pushed herself up onto her toes and kissed Dipper’s nose. “Boop! Ya mushy nerd!” She giggled, releasing her grip from his rapidly-softening penis, then pulled back a bit to survey her legs and fingers. “Eww! You’re a _messy_ nerd!” she exclaimed with a grin.

Dipper blushed despite their intimate position together. They didn’t have a towel nearby, so he grabbed his t-shirt off the floor and shyly helped Mabel wipe up.

“Well! Now that _that’s_ out of the way …” Mabel declared, she pounced on her brother, knocking them both back onto his bed. “I declare Cuddlin’ Time!” she murmured into Dipper’s ear as she rolled off him and onto her side. Dipper turned to face her, and their arms and legs naturally wrapped around each other. They squeezed each other tight, then relaxed with satisfied sighs, still in each other’s embrace.

For several minutes, the twins lay together side by side, comfortably on top of the covers in the warm night air, noses almost touching, slowly caressing one another’s skin as they whispered how much they loved each other, and how long they’d been waiting to be with one another. Dipper chuckled as he recounted how he had overheard Mabel getting herself off in that very room the previous summer on their first night returning to the Shack.

“Oh yeah? Well F-Y-I, Bro Bro, I seem to recall some serious personal time activity goin’ on in _this_ bed the very next night!” Dipper reddened again, immediately aware of the event in question. “You remember what you were thinking about that time?” she teased in an exaggerated sultry tone.

“Every moment,” he replied, immediately serious. His palm brushed hair from her face, and his hips made a small, unconscious thrust. “The two of us were stranded on a desert island. We were alone, just us … we were on the beach-”

“Was the sun shining?” Mabel asked, grinning and clamping her eyes closed.

Dipper closed his eyes as well as he remembered his fantasy of the Blue Lagoon. “Yeah. Warm, but not too hot. A nice cool breeze, too.”

“Hmmmm!” Mabel hummed happily, squirming closer, rubbing herself onto Dipper’s body. “The sounds of waves crashing, lots of birds crying, too!”

“That smell of sea salt coming from the ocean,” chimed in Dipper with a smile, getting into the imagery in his head, his hand sliding down Mabel’s ribs towards her hip.

Mabel giggled as she rolled her pelvis into him. “That crazy feeling of your brother’s _thing_ poking against you!” Dipper bashfully opened his eyes to find Mabel already giving him a saucy stare. “We were lying on our sides? Like we are now?”

Dipper shook his head slightly. “I was lying back ... you were … on top of me.”

“Oh. Like this?” Mabel murmured as she pushed herself off the mattress and carefully slid herself over Dipper, pushing him over onto his back. She straddled him at his thighs, his fully recovered erection pointing up at her chest, then she leaned forward and wriggled up his body. Dipper’s penis was now trapped against his stomach, and he gasped as his testicles and the underside of the shaft rubbed along Mabel’s vagina as she moved up his body. She ground against his length repeatedly as she leaned down to Dipper’s aroused face. “Is this more like it?” she asked teasingly.

“Uh huh!” Dipper managed to reply, his hands gripping lightly on Mabel’s smoothly gyrating hips. “You’ve … _almost_ got everything right!”

Starting to breathe harder again, Mabel smiled, eyeing the condoms on the night table. “Almost, huh?” she panted and she continued moving. “What am I not doing right … I want it to be as … perfect a recreation as possible!”

Dipper swallowed, a hand moving quickly up to Mabel’s cheek. His face turned pleading. “Mabel … “ he whispered. “Please … just let me know this is … this is what you _really_ want!”

Mabel felt spontaneous tears spring into her eyes. She slid her own hand up to her cheek and gripped his hand. “Yes, Dipper,” she replied sincerely, no hint of joking in her voice. “I love you! I’ve wanted this for a long, long time!”

“I love you so much!” Dipper breathed. Then he reached over and snatched one of the condoms. Mabel watched in amusement, continuing to grind on Dipper’s groin, as his shaking hands struggled to tear open the foil wrapper. After he managed to extract it, he looked at it obtusely, trying to concentrate through the distraction Mabel was giving him lower down. “I’ve … never used one before …I’m not sure …”

“I’ll help!” Mabel chirped excitedly, taking the disc and sliding back down Dipper’s body. He watched, nervous and excited, as Mabel held his penis steady and placed the condom on the tip. Dipper felt her warm breath on his member as she moved her face close. They both watched, fascinated, as she rolled the condom down his length.

There was a small problem: the condom was obviously too large. They looked doubtfully at the latex sheath draped loosely over Dipper’s fourteen-year-old penis. “Oh well!” Mabel declared, her smile covering up any concern that might show on her face. She scrambled back up, holding Dipper’s covered erection to her virginity with one hand and his shoulder with the other.

She lowered herself down until she felt Dipper’s tip notch into the entrance of her vagina. Then she let go of the shaft and leaned forward so she and Dipper could watch each other’s faces. “Here we go …” she whispered, hiding her nervousness as she began to bear down.

As she pushed down, nothing happened at first. She felt Dipper pushing up at the same time, increasing the pressure. Mabel bit her lower lip. Then some of the friction was suddenly overcome, and over an inch of Dipper’s length penetrated at once. Mabel couldn’t mask her discomfort as she was stretched painfully.

Immediately relaxing his pelvis, Dipper’s hand went to her face. “I’m hurting you!” he said, alarmed.

Quickly wiping her eyes, Mabel said, “No, I’m okay! I’m fine! Let’s keep going!”

Being a virgin, Mabel didn’t know she really wasn’t prepared to have sex. She was tight and a bit nervous, neither of which make any girl’s first time easy. Between herself and the rubber, there was too much friction for their coupling to go smoothly. And Dipper wasn’t free of discomfort himself. Being unfamiliar with condoms, the twins had no idea that he was supposed to pull back his foreskin prior to rolling on the rubber. The loose sheath was now folding up at the tip and pulling the foreskin down over the head as he entered Mabel. The delicate, normally protected skin of the head began rubbing tightly against folds of latex without any lubrication.

Mabel was determined that she would show Dipper the full amount she loved him, even if this hurt her a bit. Impulsively deciding that the “ripping off the band-aid” method was the best way to go, she took a deep breath and dropped down with all her weight.

Both twins cried out in pain. Tears ran, uninhibited this time, down Mabel’s cheeks. Dipper clenched his teeth to keep from shouting as the bunched up condom dragged across the exposed tip. She gingerly lifted herself back off, the condom coming loose and yanking off of Dipper’s penis, stretching and rubbing at the sensitive head again as it came away. This caused another exclamation of agony that Dipper muffled with his own hand. Mabel was sitting beside him now, doubled over trying to deal with the awful experience of a deep, unlubricated first-time penetration.

Soos’ voice called up from the bottom of the stairs. “Hey dudes! You all right?”

Dipper took a deep breath. “Yeah Soos!” he yelled. “I just … stubbed my toe! I’ll be fine!”

“What about Hambone?” Soos continued. “I swore I heard Mabel scream, too?”

“It’s okay!” she shouted shakily. “I … I stubbed my toe, too!” Dipper gave Mabel and incredulous look. Mabel shrugged back helplessly.

“Woah, random number theory! What’re the odds?” Soos called back. “Ya want ice packs, or anythin?”

“We’re good!” they yelled back together.

The twins spent the next few minutes recovering, getting over the panic, pain, and embarrassment. At first they had trouble looking at one another, now uncomfortably naked, not feeling at all sexy. Dipper turned his head away while Mabel held her shins in an invisible Sweater Town position.

Mabel shifted, inhaling uncomfortably as the nerve endings in her crotch protested. Finally, she broke the silence. “Guess that coulda gone better, huh?”

Dipper snorted derisively. “Yeah, you think?” He rolled over away from Mabel to hide his face and his sore and completely flaccid penis. “I’m sorry,” he said softly after a short silence.

“I'm sorry too,” Mabel mumbled. Then a moment later, she smirked and put her palm on Dipper's hip. “And sorry to Mr Dipstick, there!” she chuckled softly as she slid her hand down to try to tickle his genitals.

Still upset, Dipper squirmed and pushed Mabel's hand away. “Mabel, I _hurt_ you! How can … how can you even want to touch me again?” he said bitterly. “I wish that … I’m just sorry we did all this at all!”

“Hey!” Mabel replied, caressing his arms and back. “I'm not sorry about _that!_ I mean ... yeah, that really didn't live up to the harlequin romance level first-time experience there, but _we_ experienced it. _Together!_ I would _never_ have been able to handle having anything like that happen with anyone else!” Dipper still faced away, but he was no longer trying to avoid her touches. “The Mystery Twins will figure this out! And then next time, it'll be _way_ better!”

Dipper rolled back towards Mabel, tearful astonishment clearly evident on his face. “Next time?” he asked weakly. “You … still want there to _be_ a next time?”

“Well, not tonight, for sure!” she said, laying her head on her brother’s chest and hugging his torso. “But you're not goin’ anywhere, and neither am I! You can bet your super-adorables little butt there's gonna be a next time!”

A relieved and thankful Dipper finally returned the embrace, placing a long kiss to the top of Mabel's head. She made happy, satisfied noises in return.

“I love you so much,” they said in unison, causing them both to smile even wider.

* * *

 

There was indeed a next time. Many more next times, in fact.

The following day, their first full day since arriving in Gravity Falls, Soos gave the twins the whole day off to rest from their long travel day. Mabel got to help Melody take care of little Stan Jr, while Dipper and Soos drove to town to pick up supplies. Afterward, they were given the full tour of the extensive renovation Soos had given to the Shack. Business had been so good, all the available space in the building was needed for new displays and attractions. Soos had built a large addition onto the back of the building, providing new living space for his growing family and himself, plus an apartment Grunkles used when they were home between adventures.

The only space in the older part of the structure that Soos could not adapt for tourists’ use was the attic, so it was left to be the domain of the twins for whenever they felt like coming up from the city. And for the remainder of the summer, the isolated attic provided a perfect, very private place at night for Dipper and Mabel to physically explore their new romantic relationship.

That night, Dipper showed Mabel the lubricant and “snugger fit” condoms he’d managed to buy in town when Soos wasn’t looking. They fooled around, giggling as they practised putting the rubber on the correct way, getting more comfortable and relaxed. The following nights they experimented with more touching and fingering, then with oral sex.

By the weekend, they felt they were ready to try intercourse again. This time all their preparation and practice paid off, and they both had a very pleasurable, loving experience.

For the remainder of the summer, Dipper and Mabel couldn't imagine their lives could be better. They had fun and interesting jobs, money in their pockets, no commute time to or from work, the best landlord and boss in the world, occasional visits by their favorite great uncles, and most importantly, the freedom to love each other almost without restriction. Dipper had to return to town often as the weeks went by: his visits to the pharmacy for “supplies” actually increased in frequency as time went on.

As August came to a close, their return trip to Piedmont loomed. Their last night in Gravity Falls was bittersweet, as they made love tenderly, but despairing that their hedonistic summer was done. They would be home for their fifteenth birthday on Sunday, then school the next week, but none of that seemed important at all. They snuggled and fell asleep together on Mabel’s small bed, as they had done most nights this summer, for the last time.

* * *

 

The bus ride home provided the twins hours of uninterrupted time. There were few other travellers on the coach with them.

Mabel was chattering happily about seeing Waddles and Mittens again, reacquainting with friends, and even about starting school once more. She talked rapidly, nearly nonstop. Meanwhile, Dipper brooded and said little, holding Mabel’s hand and lightly running circles over and over into her palm with his thumb.

Then their eyes met, and in an instant they both knew they couldn’t avoid it any longer.

“Mabel …” Dipper asked softly, “... what’s going to happen to us?”

She squeezed his hand back, still smiling. “Hey, Chip Dip, don’t worry! We’ll make this work, we … just have to be a lot more _careful_ , making sure Mom and Dad aren’t around, I guess …”

Dipper shook his head. “No Mabel, not _that_ … I mean, yeah we need to talk about that too … but …”

Mabel saw the worry on her brother’s face. “But what?”

He averted his eyes. “Let's say we're careful. And lucky. Mom and Dad don't notice. We manage to hide this from everyone at school.” He paused, then continued. “How long will it be before we make a mistake? How long until our luck runs out?”

“I …”Mabel started, but found she didn't have an answer.

Continuing to stare at the back of the seat in front of him, Dipper went on. “Maybe we somehow get through high school. What then? Do we go to college together? Can we keep hiding this from everyone if we do that?”

Mabel knew now that this had been bothering Dipper for some time. She waited with trepidation for him to finish.

“So we go to college. We get our degrees. Then what? … How do we hide _then?_ … We can’t ever get married, we can’t ever be normal, we can’t ever have-” Dipper’s voice cut off.

She looped her arm around his back and pulled him to her. “Dipper, whatever games of hidin’ and seekin’ we need to do, we can do it! We’re still the Mystery Twins, figuring weird junk out!”

“Or …” Dipper’s voice hitched. “... or what if … one of us doesn’t _want_ to keep hiding? That keeping this secret just gets to be so much … y- one of us starts thinking it’s not _worth_ it ...”

Mabel heard the slip in Dipper’s explanation. He was afraid she would break up with him when it became too difficult to continue masking the truth of being in a secret and forbidden relationship. That he thought she would dump him when the going got tough.

“Dipper Pines, look at me!” she interrupted.

Reluctantly, Dipper turned his head towards his sister. He knew he was in trouble, that she had heard that he thought she would be the one to break things off someday.

But instead of anger or hurt, he saw nothing but affection and sincerity on her face.

“I _love_ you, Dipper. I’ve known that for two years, but now I can say that, in a way, I’ll have loved you _fifteen years_ tomorrow! You are more to me than anyone else _ever_ could be!” She placed her hands on his cheeks. “We were born a pair, and we’ve always had each other. I _know_ that I never, ever want to you lose you!” She felt tears running between her fingers. “I want to be with you, no matter what! Maybe we have to be sneaky, maybe we tell Mom and Dad someday, maybe we let the whole world know they can kiss our cute matching asses … I can’t imagine what my life would be like without you, Dipper, and I _never_ want to find out! Get that into your big ol’ brain! Okay?” she cried quietly, her cheeks now as moist as her brother’s.

Dipper sobbed loudly while reaching out to grab Mabel, desperately pulling her to him. They cried openly as they hugged and kissed with fervent need, uncaring if anyone around them was watching. They might not have all the answers of what lay before them, but both of them now knew that they were committed to face the challenges ahead _together_. They were in love, and that was all that really mattered.

* * *

 


	5. Part 5 - Perfection

* * *

## Autumn 2014

The twins were laughing and jostling on the couch while playing Super Smash Bros. It was a Saturday evening in November, and they had been playing most of the day after picking up the game on its release day the night before.

“Dipper? Would you please come up to your room?” called down their mother from the top of the stairs.

Mabel controlled Sonic, and was on the verge of defeating Dipper’s Mario, but he had just landed a combo to increase her damage past 90%. “Just a sec!” Dipper called back without taking his eyes from the big screen television.

“Right _now, please!_ ” came the stern reply from their mother.

Dipper froze at the tone of voice, and Mabel immediately commanded Sonic to finish off Mario with Sonic’s Smash Attack, ending the round. Already thrown out of sorts by his mother, Dipper threw a death stare at his sister as he rose from the couch. “Really?” he grumbled.

Mabel looked back with a guilty smile and performed a weak pump of her fist. “Boo ya?” she replied quietly.

Rolling his eyes and dropping his controller on the sofa, Dipper headed up the stairs, taking them two at a time. When he arrived at his room, his mother was standing in the hall, directing him inside. As he turned, he noticed his father seated in his desk chair, waiting. Nervously, he sat on his bed as his mother closed the door.

His father leaned forward. “We’ll get right to the point, son,” he said, raising his hand from where it had been resting palm down on his lap. Dipper’s eyes widened in shock as his father presented him with the nearly empty box of condoms that had been hidden in his desk drawer. Then his chest constricted in near panic as his mother reached to the floor to pick up Dipper’s trash bucket. He noted most of its contents had been emptied, and he knew exactly what he’d be seeing: latex sheaths that had been quite clearly used for their intended purpose.

Dipper immediately assumed that it was all over: his parents knew about his relationship with Mabel! They would split the twins up, they’d send him to juvenile prison, they’d disown him, they’d castrate him, they’d- … Dipper’s brain short-circuited from all the terrible things he imagined was about to happen in the next few seconds. He began hyperventilating in panic.

“Whoa, settle down, Dip!” said his father. He rolled the chair forward and put a calming hand on his son’s shoulder.

His mother knelt down to eye level. “It’s okay, Dipper! Your father and I just want to talk with you. Don’t pass out on us here, okay?”

Enough logical thought remained in Dipper’s brain to realize that his parents would not say “it’s okay” if they knew that their children were having sex with each other. He forced himself to try to calm down as his father continued to hold his shoulder.

“Look Dip,” his father said gently, “we’re just a little concerned over why you’re … _practising_ … with these condoms so much.” He released his grip on his son and scratched the back of his head.

“You’re only fifteen, Dipper,” his mother continued, her voice authoritative, but concerned. She steadied herself before she could go on. “Are you …” She closed her eyes. “Are you already sexually active? Have you been out having sex with someone?”

Dipper realized that he had a chance to get out of this. He just needed to be convincing: he had to lie straight to his parents’ faces, and he wanted to make it believable. They could not be allowed to guess the truth. But he was mortified and frightened.

“No.” he answered simply, mumbling and avoiding eye contact with either of the adults in the room. “I’ve never had sex.”

Dipper’s mother knew him very well. Her eyes narrowed. “You’re sure?” she asked, suspicion obvious in her voice.

“Yes, Mom!” he responded with earnest embarrassment, face red. “I’ve never … you know .... ‘been’ with anyone … I mean, jeez Mom, I’ve never had a girlfriend or even close to one … you know, it’s like Dad said …” he moaned, waving at the bucket of evidence, “... practise … by myself … that’s all!” he finished, cringing pitifully.

After watching his face for a moment, his mother’s face relaxed. “All right,” she relented. “I’m sorry, Dipper. It’s just that … I know that we haven’t talked a lot about this, but … you know that your father and I both waited for one another, right?”

The only thing worse for Dipper than talking with his parents about him having sex was talking with them about _his parents_ having sex. Dipper’s skin darkened even more. “... Yeah?”

“I know here in the city, in this day and age, things are different than they were for us when we were young,” she said, gripping her husband’s hand. “It was easier for us to not get all drawn in … for us to be a little more innocent, I guess?”

His father cleared his throat. “This isn’t news, but your mother and I both came from pretty strict homes, Dipper. Your Grandpa Shermie made sure I was in church every Sunday. We had no unchaperoned dates, the whole old-fashioned deal. I actually asked your grandfather for his daughter’s hand in marriage before I asked her!” Dipper rolled his eyes, as he already knew this and really didn’t want to talk about it. “Yes, it was out of date for me to do that, even then. That was only seventeen years ago.” He squeezed his wife’s hand. “We were both virgins until we married. And again, yes, we _know_ how unusual that was then, and certainly how rare it is now!”

“But there’s something to be _said_ for saving yourself!” Dipper’s mother interjected. “We just … want you to know that you don’t _have_ to … have _sex_ with a girl just because you _like_ her. You don’t have to be in such a hurry!” Then her face relaxed and she chuckled softly. “I know, I know … hormones make things so hard! I have to admit … if we weren’t chaperoned ... “ she began to show a blush of her own, “... I daresay we might not have made it to our wedding night as virgins, either!”

“Oh god!” moaned Dipper quietly, his chin on his chest.

Dipper’s father looked amused at his son’s discomfort, then he sobered. “Son, we can’t stop you from doing what you want. If … if you’re planning on being sexually active, well … using a condom is exactly the right thing to do.” He stopped to nudge Dipper, and the teen reluctantly lifted his head to face him. “We just ask you to consider what we’re saying here. There’s a _difference_ between just having sex, and making love! I’m sure you may find that sex would feel great. But when it’s not just sex … when you don’t squander your _one chance_ you have, to be able to experience _making love_ with someone you just _know_ you want to be with for the rest of your life … it’s … it's simply the most _incredible_ feeling you will ever know!”

How could Dipper tell his parents that he already understood _exactly_ what his father was saying? He swallowed hard, willing himself not to show any of the emotion that struggled to escape.

“We love you, Dipper,” said his mother, “and we’re sure this was not the conversation you wanted to have. Just please think about what we’ve told you, okay?” Dipper nodded in reply, and his parents both gave him a kiss on top of his head as they left his room and retired to the master bedroom.

Heart still beating like crazy, Dipper slowly made his way back down the stairs to the family room. When she saw he was alone, Mabel leaped to her feet and grabbed his hands.

“I couldn’t make any of that out, but that sounded kinda intense!” she whispered urgently. “What happened?”

Dipper wrapped his arms around his sister, and he immediately started feeling the pressure release as she squeezed him back. Quietly he replied, “They found my condoms.” He felt Mabel tense, and added, “It’s okay, they don’t suspect us. But …they were kind of disappointed that I had them. I made them think I was using them to practise, and now they think I want to sleep around!”

Mabel snorted, relaxing and pulling back to smirk at her brother. “Dipper, you big ol’ slut!” she teased, cuffing him on his shoulder.

“Not funny!” Dipper groaned, keeping his arms around her waist. “This is kind of serious, Mabel! They’ve pretty much made it known that they still don’t like the idea of either of us thinking about sex before marriage. So now, what’s gonna happen if they find I’m still using condoms? The ‘practise’ excuse is _not_ going to cut it again! They’ll start wondering exactly why I’m still using them here in the house, and then they might go looking in your room, too!”

“That … would _not_ be so great!” Mabel deadpanned.

Dipper held her tighter. “I love you, Mabel. Nothing will ever change that! But without the condoms, we might not … we might not be able to … make love anymore!” Dipper was on the edge of tears with the thought.

Mabel brought her hands to Dipper’s face and turned his head towards her, her lips quickly seeking his out. After a long, comforting kiss, she used her thumbs to wipe his tears, and murmured, “Maybe …” and then with a crafty look, she continued, “... maybe not!”

* * *

 

The following Monday, Mabel began her monthly period. It had never been an altogether pleasant experience, but she had never raised much of a fuss in the past, either.

However, this _particular_ month Mabel complained much more about the severity of her cramps. The pain was excruciating, she wailed. Wasn’t there something to be done about this? She couldn’t deal with this discomfort!

An urgent appointment with the family doctor was quickly made. After listening to Mabel’s description of her pain, the doctor diagnosed Mabel as having dysmenorrhea. The easiest treatment for the symptoms, she explained, was to be on a daily regimen of COCP, a combination of estrogen and progestogen which reduces the intensity of the monthly cramps.

The medication’s more well-known prescribed usage, of course, was that of being an extremely effective method of birth control, and was commonly called “the Pill.”

They left the doctor’s office, Mabel with the prescription script in her hand. They got into the car and headed to their pharmacy.

“Mabel ... “ her mother said as she steered her way through the suburban traffic, “you know what most people use these pills for, don’t you?”

“Mom!” Mabel groaned, blowing her breath through her lips dramatically.

“I’m just saying, please be … _discreet!_ All right? I understand you need them now, and that the Pill is the best way handle your pain. But don’t let everyone in your school know you’re on them, please. Kids will talk, and word will get around. Some young people will get the wrong idea about you.” She glanced worriedly at her daughter. “Your father and I know that you’ve wanted to start dating for awhile now. Maybe after Christmas, we’ll see how it goes. But if you have a reputation, if everyone knows you’re on contraceptives … you might get a lot of unwanted attention … and get pressured to do things you might want to think about … _saving_.”

Mabel blushed brightly, embarrassed and extremely worried that her mother would ask her directly if she had ever been active sexually. She had never been able to lie to her mother effectively, and she doubted today would be the day she would acquire the skill.

Her mother sensed her discomfort as they waited at a traffic light. “We don’t have to do this now, but we need to talk about these things. How about we agree to hash this out the next time you ask me when you can start dating?” She smiled sneakily. “Maybe I can keep you my little girl just a wee bit longer!” She turned her attention back to the road as the light turned green.

Mabel saw that her mother cared for her daughter’s well-being as well as her daughter’s reputation. “Okie Dokie!” she replied with an over-the-top pout, making her mother smile wider.

Inside, she felt guilty for misleading her mother, but still relieved that her plan had worked out. Having to keep condoms hidden wouldn’t be an issue for Dipper or her much longer.

* * *

 

It was the morning after Thanksgiving, and the twins’ parents had left to see what “Black Friday” specials could be had. Their father had asked if the kids wanted to come, but they had declined. Their mother told them to fix turkey sandwiches for lunch, and not to expect their folks to return until late afternoon. Dipper and Mabel managed to wait ten minutes after being left alone before they were certain the car wouldn’t come back into the driveway. Mabel commanded Waddles to stay, then grabbed Dipper’s hand and they tore up to her room. Urgently, they clutched one another and smothered each other’s mouths with kisses.

“Oh Mabes-” Dipper gasped desperately. “-I’ve missed you-” kissing her again, “-so much!”, recalling their private conversation where she told him they had to wait until after she started the pills, and for her period to finish, before they could try intercourse again. The medication had arrived in plain brown packaging on Wednesday. Two days later, this had been their first chance to be alone.

Mabel moaned loudly, loving the feeling of Dipper’s mouth on hers, his arms around her, one hand in her hair and the other squeezing her butt. “What's s'matter?” she teased. “Can’t handle-” “-Mabel deprivation-” “-for even-” “-a week?” she giggled between kisses. Her own hands moved over Dipper’s body sensually.

Panting, Dipper pulled his lips away, moving his palms to the sides of her head and gently weaving his fingers into her hair. He kept their noses and foreheads pressed together. “I don’t think I can handle Mabel deprivation _ever again!_ ” he breathed, eyes less than an inch away from hers, wide with love and devotion. His chest almost hurt from the effort of trying to communicate the intensity of his emotions to his sister.

Mabel’s insides did that melty-squishy thing that they always did when Dipper would say something earnest and passionate about how he felt for her. Her hands slid up to his cheeks, caressing the edges of his ears, eyes, and mouth with her fingertips and thumbs. Her every sense was filled by her brother, no other distractions invaded.

“I love you, Dipper,” she squeaked.

“I love you too, Mabel,” he whispered back. The twins melted together again, gradually lowering themselves onto her bed.

Neither of the teens had changed from their sleepwear that morning: ridding themselves of their sleeping shirts and underwear took very little time at all. They moved as one, rubbing their nude bodies together as they clutched onto one another tightly. Their fingers and mouths tickled and probed each other, their foreplay quickly escalating the level of their arousal.

Mabel rolled onto her back and pulled Dipper on top of her between her legs. “No need to unroll onto the pole,” she growled as she reached between them to grasp his penis.

Dipper shuddered as he allowed Mabel to lead him to her vagina. She guided his tip to her clitoris, allowing him to rub her button deliciously along his length with several pushes of his hips. Then as he pulled back for another lunge, she aimed him lower. He sank all the way into her in a single stroke.

“Oh god!” Dipper groaned. “This feels … _so_ much better!” He instinctively began slowly thrusting, completely lost in the delight of the warm and wet friction on his member.

Mabel quivered, feeling ecstatic shocks of pleasure. She loved the spontaneity, the lack of needing to stop everything for a condom. And without the rubbery texture, Dipper felt smoother inside her, almost like velvet. The sensation of his slow, careful movements was phenomenal.

The twins were experiencing complete and total intimacy for the first time. The final barrier between them was at last removed. They gazed at one another in wonder, almost shocked with the indescribable feeling of completion.

Then the dam broke. Dipper’s mouth crashed down onto Mabel’s as she used her arms and legs to squeeze his body to herself as securely as she could. Unashamed moans and cries of passion accompanied the sounds of creaking bedsprings and of skin slapping together rapidly. Nothing mattered now except helping each other reach their peak together. After only a minute or so of frantic lovemaking, they desperately held each other tight and cried out loudly as they both climaxed. They had never felt closer or more love for each other than at that moment, as Dipper’s penis delivered his semen unimpeded to his sister's cervix.

Teenage exuberance helped them make love four more times that day before their parents came home. They made each time last longer than the time before, and they were happier than ever with their sex life. It wasn’t just the feeling of complete closeness: the lack of latex made Mabel feel less dry than she had experienced before, and Dipper had far more sensitivity. They both came to the conclusion that although not using a condom was a bit messier, there was no doubt that they would never use one again if they could help it.

* * *

 


	6. Part 6 - Conception

* * *

##  Winter 2015

Dipper was in his room, packing his bags. Lightweight shirts and shorts joined several books and his new tablet in the suitcase. He also packed his swimsuit, smiling knowingly to himself at how little he hoped it might be worn in the coming week.

It was after dinner on Friday night, and the family was preparing to leave the next morning to go south for March Break vacation again. In fact, at Dipper and Mabel's suggestion, their parents had booked a week at the same hotel as the year before. The twins had made sure to let their mother and father know how much they had enjoyed themselves the previous year, and had no objection to returning to the same resort. 

The teenagers had been quietly thrilled when they learned they were going to the resort a second time. Surely they would have the opportunity to sneak away to the nude beach again? And a hotel room to themselves! It was stressful to spend any pleasurable time together in the house: even on the occasions their parents left them alone, they always worried that they might be caught by anything that could bring their parents home early. At the resort, they would have six nights of total privacy! Dipper hadn't had any opportunity to fall asleep in Mabel's arms since the previous summer in Oregon. And that was in the uncomfortable single beds in the stuffy attic of the Mystery Shack, a far cry from high-end queen-sized beds in an air conditioned hotel room. Dipper was pumped for this to be the best vacation possible!

“Dipper?”

Hearing Mabel's voice, Dipper turned around to his open bedroom door, a beaming smile already spreading on his face. 

His smile faded instantly when he saw his sister's grim expression. He rose from where he was seated on his chair and crossed quickly to the door where Mabel stood. “What's wrong?” he asked under his breath, aware of their parents downstairs. When Mabel didn't immediately answer, he guided her into his room to sit her on his bed, and closed his bedroom door.

Kneeling in front of Mabel, Dipper put a hand on her knee and the other on her cheek. She looked ill, and terrified. “Mabel! Talk to me! Tell me what happened!” he pleaded. 

Mabel bit her lower lip, clearly trying to not burst into tears. She raised a shaky hand, holding a narrow plastic stick. She turned it to hand it to Dipper by its handle. In confusion he took it, examining the markings. 

His heart skipped a beat as he realized that he was holding a pregnancy test device. Then it felt like his heart stopped altogether. 

The test result window clearly indicated a positive test result!

Dipper felt the shock rip through him, as he let the device fall to the carpeted floor. “Oh my god, Mabes!” he rasped. “Are you sure? I mean … the test could be wrong, couldn’t it?”

She shook her head. “Dip … I haven’t had a period since December!” She paused for a shuddering gasp. “I thought at first maybe it was the birth control pills messing up my cycle ... but I’ve been having weird cramps, I’m tired, I need to pee all the time, my boobs are kinda tender … it all says the same thing, Dip! The test just proves it!“ She swallowed hard. “... I’m preggers!”

“But how?!” Dipper almost demanded. “You’ve been on the Pill! Haven’t you been taking them every day, like you’re supposed to?”

“Yes, Dipper!” Mabel shot back defensively, her voice breaking. “Every day! And I wondered the same thing!” She sniffled, hurt that Dipper didn’t trust her. Wiping her face with her sleeve, she continued, “So I looked something up a few minutes ago. You remember that infection I got just before Christmas? You know, the one ...” she tilted her head, gesturing lower on her body, “... down  _ there _ ?”

Dipper was confused. “I guess? ... But obviously we didn’t ‘ _ do’ _ anything while you had that! What’s that got to-”

“Yeah, well I took antibiotics to get rid of that infection,” his sister interrupted. “And I was feelin’ fine after a few days, but I was told to finish the whole bottle. I took those meds every day for two weeks! All the way through the holidays!” The volume of her voice dropped. “... And according to the papers with those drugs, it turns out … that stuff turns my ‘baby nope’ pills into ‘baby maybe’ pills,” Mabel grumbled miserably. 

Dipper felt his heart sink, recalling that he and Mabel had found the opportunity to make love practically every day after she’d started feeling better over the two week break from school. 

“Mom picked up the meds,” Mabel continued quietly. “And even if she knew,  _ of course  _ she didn’t tell me this could happen. Why would she?” Her face crumbled, and she took an unsteady breath. “But  _ I _ should’ve read those papers! This is … this is all my fault!” she sobbed.

“No, Mabel!” Dipper whispered urgently. “ _ I _ should’ve known! I’m the one who likes to read stuff like that … maybe we might have held off, or I could’ve worn a condom …” he babbled as his panic rose. “I mean … this is more  _ my _ fault than yours! If I hadn’t been so scared of getting caught with the condoms in the first place, then …  it’s just … Mabel,  _ what are we gonna do?!? _ ”

“ _ I don’t know!! _ ” she squeaked in reply, nearly hysterical. “I  _ can’t _ … and we can’t … and if …”

Dipper immediately forced himself into analytical mode. It was hard, since he wanted to try to comfort Mabel, but he could feel himself starting to hyperventilate. Only arriving at a solution mattered now, so he pushed aside his panic and personal feelings. “Okay, okay! We’ll figure this out! Just … just let’s settle down and go over our options.”

Mabel sniffed, wiping her eyes. She trusted Dipper to help them stay strong together. “... Okay.”

“All right,” Dipper said, thinking quickly. “Option one. We tell Mom and Dad, and-” he screwed up his face doubtfully, “they help us figure out what to do?”

“Dipper, they’ll be furious! What will they say? What will they  _ do _ to us?”

“I know, Mabel. But we’ve got to think of everything we  _ can _ do, and pick the one that’s the best choice. Okay?” Mabel nodded reluctantly. “Option two. You …” he avoided looking at Mabel, “... get an abortion.” He felt sick as he suggested it. 

Mabel cried softly into her hands. “I … I don’t know if I can do that!” she weeped. “Before I came in here … I’ve already thought about that … but after spending the summer with little Stan Jr … it’s just  _ not the baby’s fault! _ ”

Dipper nodded grimly, but had to move on. “Option three … we run away. Both of us.”

“How would  _ that _ work?” Mabel almost barked. “We’re  _ fifteen _ , Dipper! Where are we gonna go?”

“... Gravity Falls, maybe? Move in with Soos and Melody?” he suggested weakly. Mabel again buried her face in her hands as she considered the possibility that everyone they knew in Oregon, including their great uncles, would find out about them. “I don’t know, I’m just thinking here!” Dipper cried.

“Yeah I know!” Mabel said pitifully. Then she peered up at Dipper again. “Any other options?”

Dipper shuffled, looking very uncomfortable. He knew there was one option left. A really bad option. One that was  _ permanent _ , an option that there was no coming back from. 

He considered it quickly, and immediately despised himself for it.  _ No _ , he thought,  _ I will NOT suggest to my sister that we could kill ourselves! Surely it could never get bad enough for that! I won’t LET it get that bad! _

“No,” he answered quietly after a lengthy pause. “Those are the only three possibilities.”

“What about raising the baby? What about giving it up for adoption?” Mabel asked desperately.

Dipper shrugged apologetically. “Both of those decisions come after we choose between telling Mom and Dad, or running away. It’s still one or the other. Or … or abortion ...”

Mabel balled her hands into fists and brought them down hard on her thighs. “Oh Dipper, I hate myself for this … but … what do  _ you _ think we should do?”

He sighed heavily. “Well, there’s only one option that doesn’t completely change our lives … but …”

“... but we’d have to …  _ kill _ our baby …” finished Mabel, her voice barely audible.

“I don’t like it either, Mabel,” admitted Dipper. “It’s the  _ easiest _ option. We sacrifice the least. And … it  _ is _ your body, so … you don’t  _ have _ to go through with this ...”

Mabel stared unfocused and silent for over a minute. Finally, she slowly shook her head. “I can’t,” she whispered. “I can’t kill our baby … I just can’t do it …”

Dipper carefully leaned forward and hugged Mabel tight. He would never have tried to convince her one way or the other. Dipper believed that the decision to abort her pregnancy or not was her, and only her, right to make. He wanted to her to know he supported her choice fully. 

“Then, we have only two choices left,” he said as he continued to hold her in his arms. “We tell Mom and Dad, or … or we run.”

The twins talked and cried for over an hour after that. Running away only made sense as an option if they intended to keep and raise their child. Did they want to do that? Would they be able to hide the truth of the baby’s father? Even if they could, were they prepared for the accusing looks and nasty comments that Mabel would face for having and raising a child while so young? Would Mabel ever be able to get a normal education? 

But if they chose to give the baby up for adoption, what then? Could they bear to have their baby taken from them, knowing the life they’d created together was out there in the world, without them? 

And putting aside all these other questions, would the baby be healthy, given its incestuous conception? Could Mabel and the baby receive good medical care during her pregnancy?

Facing all these questions helped focus the two choices they faced. Finally, they decided which path they needed to follow. They kissed each other deeply and whispered words of love and devotion to one another, confirming that they’d always been there and would always be there for each other. No matter what. 

Twins forever.

* * *

 

“Dad?” said Dipper carefully from the threshold of the door to the study, where his father sat typing at his computer.

“Hey Dip!” replied his father. “Just finishing up some office work. Stuff’s got to get done before I can leave for a week.” He swivelled in his chair to face his son, glancing at his watch. “It’s getting late. You almost finished packing? You know we have to get up early.”

The teenager shuffled awkwardly. “Yeah. Can you just come out to the couch, please? Mabel and I … we need to tell you something.”

The elder Pines raised an eyebrow. “That sounds ominous!” he said. 

Dipper didn’t respond, he simply headed to the living room to join his sister, who was just arriving with their mother in tow. He knew his father was following behind him.

“Mabel, I’m very busy,” their mother was saying. “I was late getting back from dropping Mittens and Waddles off at their pet sitters. I don’t want to be up all night packing.” Mabel convinced her to sit on the sofa, where their father joined her. “So what is this all about?”

Mabel sat down on the love seat that faced the sofa, and Dipper sat next to her. They looked at each other nervously, nodded, then Dipper spoke. “Dad? Mom? You’ve always said we should just get to the point, right? That we’re just wasting time otherwise?” Both parents verbalized their agreement. Dipper looked back to Mabel.

She paused, took a deep breath. “I’m pregnant,” she said, her voice betraying the terror she felt.

Both parents drew a sharp intake of breath. Mabel cowered instinctively and her hand sought out Dipper’s. He took her hand without hesitation and squeezed it hard, drawing strength from Mabel as much as he lent strength to her. 

He took a deep breath of his own. “And I’m the father,” Dipper said, his voice cracking.

Never let it be said that Dipper and Mabel’s parents weren’t fine people. They loved the twins, and worked hard to provide for them. They were old fashioned, but willing to grant that their kids might not want to follow their traditions. So given the double nuclear bombs that their two children had just dropped on the family in a five second span, they took the news about as well as could have been expected.

But that doesn’t mean it still didn’t get ugly.

* * *

 


	7. Part 7 - Parturition

## Autumn 2015

Dipper leaned across to the older student's textbook. “So you can determine the linear function which takes value f of a at a, and f of b at b, by this formula,” pointing at an equation, “because the first term is 0 when x is b and is f of a when x is a, while the second term is 0 when x is a and is f of b when x is b.” He paused, searching for comprehension in the face of the teenager beside him. “Understand?”

The young man beside him wore the jacket of the Westfield High football team. He looked back dumbly. “No, man! This calculus shit is hard! You gotta slow it down, okay?”

Inside, Dipper screamed in frustration at this idiot's lack of even basic intelligence. Outwardly, he smiled politely. “Okay, no problem. Let's see if I can explain it another way…”

Since he’d showed up as a newcomer to the mid-sized New Jersey town at the beginning of summer, Dipper had gained a favorable reputation as an excellent tutor. He worked long hours over July and August with teens requiring assistance with their remedial summer classes, and now with regular schooling resumed, he worked afternoons and evenings as well as all day on Saturdays.

The jock was Dipper's last client of the day. The town’s library, which didn't seem to mind if he used it as the base of operations for his tutoring business, just announced closing time in ten minutes, meaning it was almost nine o'clock. Dipper yawned, dreading his own homework which he had yet to touch.

His cell phone buzzed, and he glanced at the screen. And suddenly he was not tired at all!

“Sorry gotta go no charge for today's session bye!” Dipper spewed as he hurled his books into his bag. Seconds later, he was out the library doors into the late September evening, on his bicycle, and pedaling home as fast as his legs could get him there.

* * *

Mabel reflected on all that had happened over the last several months. The memories flew by in a rush.

_The emotional trauma of that night in March when she and Dipper had confessed to their parents. How it had taken hours between the yelling and crying to explain what had happened between her and her brother over the last year, and the feelings over the years before that led up to their relationship. How they made their parents at least begin to understand that their love, wrong or not, was genuine. And how Mabel was determined to keep the baby._

_The week that followed. Their vacation cancelled. Endless accusations and demands, outbursts and pleading. Negotiation. Questions. Research. And finally, reluctant agreement on a plan, a plan of action for the whole family._

_The remainder of the school year. Bulkier sweaters than usual. Suppressing the nausea. Uncomfortable deflection of questions from friends about the upcoming summer. Stealthy packing of belongings on weekends and after school._

_Moving out of the only home she and Dipper had ever known at the end of June. Moving to a smaller house in a new town across the country._

_Continuing to grow ever bigger throughout the summer. Learning the skills necessary to be a parent. Laughing ironically at the way she waddled like her pet pig. Complaining about the pains in her back. Crying about how inadequate and unprepared she felt._

_She and her brother’s sixteenth birthday. Celebrating quietly and uncomfortably, no one but the four of them in the house. Sharing a brief kiss under their parents’ watchful, disapproving eyes._

_Registering for school. Enduring the silent scorn of the other students. Lying about the parentage of the baby, telling anyone who cared to speak to her that the father was in California._

_Watching Dipper labouring harder than ever before in his life. Working to be financially supportive. Working to continue to get top grades in school. Working to learn how to be a great father. Always working, tirelessly._

_The strange experience of feeling her water breaking the previous night. Texting Dipper to come home immediately. The entire family rushing to the hospital as she began to feel contractions._

_The pain. The unbelievable pain! The patient, soothing words of encouragement and support from her brother, whom she wanted as her coach. The unintentional hilarity of seeing him almost pass out as the delivery reached its climax._

All these memories flashed by in an instant, all the hardships now undoubtedly worth it. As she lay exhausted on the delivery room bed, with her brother hovering by her side, she was holding an incredible, tiny, brand-spanking new person in her arms! Their daughter. She and Dipper had made a beautiful, perfect little girl!

* * *

The following evening was a Thursday. Dipper knew Mabel and the baby were discharged from the hospital after lunch some hours before, but he had been at school and then the library all day. Excited, he bicycled home as quickly as he could, arriving home shortly after nine.

Dipper’s father, as per usual since their move to the east coast, was busy in his basement office with late-night work. His mother was also home, emerging from the laundry room after doing the first of what would be hundreds of loads of clothes and towels in the coming year. Dipper gave Waddles a scratch behind the ear, before finding his sister in the house’s modest living room, sitting in a rocking chair and breastfeeding their infant as she hummed a lullaby.

She lifted her head as Dipper came in. She looked haggard and dead tired, her hair a tangled mess, and not a trace of makeup. And she smiled at him.

He swore to himself that she had never looked more beautiful!

Dipper heard a soft snort of suppressed amusement beside him. He turned to see his mother was smirking at his awestruck face, recognizing that look of hopelessly complete love. Then her expression softened, and she tilted her head towards Mabel. He smiled gratefully to his mother, then quickly padded over to his lover and daughter.

His mother watched the young couple and their child, a war of emotions within her.

After finding out about Mabel’s pregnancy, she and her husband had eventually respected Mabel’s desire to keep the baby. But they knew they couldn’t just leave their children to be exposed to the terrible treatment that would surely come, once the neighborhood and school found out Mabel was pregnant. In particular, they anticipated that there would be rumors that perhaps Mabel’s strangely-close twin brother was the father, rumors that would be impossible to disprove. The innuendo and shaming would have been horrific, and legal authorities might even have gotten involved.

Their father had been granted permission from his tech company to quickly transfer from the San Francisco head office to a branch office in Newark, but he regularly was required to be available on west coast time for additional assignments. Their mother closed down her real estate business in Oakland, and was taking a hiatus from trying to begin again in New Jersey until Mabel and the baby no longer needed her. For the sake of protecting their children, both parents had given up or damaged their career paths, leaving the family with much less money and a far more uncertain retirement plan.

The twins’ father quietly climbed the stairs from the basement and hugged his wife from behind, resting his chin on her shoulder and also taking in the scene before them. The twins were oblivious to their presence. To their parents, Dipper and Mabel looked like any young couple in love.

But few couples had to deal with their circumstances. The decision to keep the baby had also forced Mabel and Dipper to sacrifice greatly. Their parents had forbidden Mabel from even considering dropping out of school, as so many teen mothers do. The local school board was piloting a program that gave teenage mothers four weeks of maternity leave from high school attendance, provided she continue to complete school work at home. After this, Mabel would return to school every day while her mother cared for the baby, an arrangement her mother agreed to for a year. After that, the child would need to have daycare, and that needed to be paid for. Two years of school and homework while raising a baby was a formidably difficult plan.

Earning extra money was Dipper’s sacrifice. To ensure that he lived up to his responsibility as the child’s father, he would have to work long hours in addition to school. All his earnings were to go into paying for the baby’s needs and health care costs, costs that were not covered by their father’s benefit package. Anything left would go to savings to pay for future daycare expenses. He had no reluctance for this, but he did have some regret that he would not legally be the baby’s father. The documents would be registered with the father listed as “unknown”, and he admitted that it would be less complicated for the child if she were to officially be just his niece. They had plenty of time to decide how they would tell their daughter about her parentage when she got older.

The final sacrifice was the hardest to accept: the twins were forbidden by their parents any physical intimacy. This was non-negotiable for their parents, regardless of how strongly Dipper and Mabel felt for each other. For their only children to be sexually active together was simply unacceptable, a mistake that would not be permitted to be repeated. Beyond “normal” brother and sister behavior, they would only be allowed short kisses on the lips, and only when the teens were at home. The parents promised _very_ unpleasant punishment if they ever found out this rule had been broken, not the least of which would be the loss of any chance of restoring trust in their kids. They did, however, acknowledge that if the twins still felt their unnatural romantic attachment to one another after a year of parenting, they would grudgingly revisit this issue at that time.

Ultimately, both twins had accepted the terms laid out. They agreed they had to show their parents that they were serious about their child, and about each other. If their parents could give so much up for them and their well-being, and allow them to remain under the same roof even after such a colossal error of judgement on their part, they could withstand the challenge. They promised to take this “mistake”, and make it into something wonderful.

The twins’ mother held tight to her husband’s arms as they watched the scene across the room. Then she turned her head to peer at his face. He looked back. She wordlessly communicated a simple question with a sideways glance of her eyes and a sympathetic expression: _Maybe, just this once, we could give them some time to themselves?_ After a brief pause, he gave her a small smile and a nod.

They gave one last long look at their children and grandchild, then turned and went to their bedroom.

* * *

“She’s amazing!” Dipper whispered in awe as the infant suckled on Mabel’s breast.

“Yeah!” Mabel replied quietly. “I can’t believe just how amazeballs she really is!”

They watched in silence for another minute as the baby appeared to have taken enough. She coughed, then began to cry. Mabel pulled her shirt back into place, threw a towel over her shoulder, and gingerly lifted the squawking little human up to her shoulder, giving gentle pats to her back. Mabel laughed in delight as the cries were interrupted for a second by a large burp, and a substantial stream of milky spit flowed out of the baby’s mouth onto the towel. She then resumed crying, somewhat less urgently now.

Obliquely, Dipper couldn’t believe how happy he could be while wiping up baby puke! He smiled stupidly while studying the little girl’s features and running a finger delicately through her wisps of thin, wavy brown hair, and then lovingly caressed her forehead with his thumb.

Soon enough, the infant’s cries grew weaker as the milk settled into her stomach. Mabel supported her head and pulled her down onto her back, cuddling her securely in her arms. The baby made a big yawn, accompanied by an adorable squeaking sound, and fell asleep within a minute.

“We’re gonna be just fine!” Mabel murmured to the baby as she carefully stood up with her precious bundle. “You’re absolutely perfect! I’ll try to keep remembering that as you get bigger!” she giggled softly.

Dipper chuckled. “And you’ve got no idea how awesome your Mommy is,” he said as he embraced his sister from behind and nuzzled her neck while gazing down on their child, unconsciously duplicating the same position as their parents from minutes before.

“I _am_ pretty awesome!” she agreed, addressing her baby. “But your Uncle Dipper? He’s just heckin’ _ridonkulous!_ He’ll be all the Daddy you will _ever_ need, I guarantee it!” She turned to look playfully into her brother’s face, their cheeks pressing lightly against one another.

He held her body closer and longingly stared into her eyes. He tried to speak, his mouth opening and closing twice, and his eyes becoming wet.

“I _love_ you, Mabel! … So, _so_ much! More than _ever!_ ” He looked apologetic at the inadequacy of his words.

Tears began flowing down Mabel’s face as she reached for his lips with her mouth, and as they kissed, Dipper slid around to face her. He held them both, the two most important things to him that had ever existed. He felt giddiness and warmth unlike ever before, as he and the love of his life kissed, with their sleeping child nestled between them.

As their lips parted, Mabel whispered, “I love you, too, Dipper.” They rested their foreheads together happily and admired their innocent daughter.

“And as for you, little one,” Mabel said softly, leaning down to kiss the baby’s forehead, “you need to go to bed so we can do our homework!” Dipper reluctantly released his hold, then felt his heart jump as Mabel motioned for him to take the baby. Ever so carefully, they moved the infant from her mother’s arms to her father’s. After a brief moment, Dipper was followed by Mabel into her bedroom where the baby’s crib was waiting. After duplicating the forehead kiss, he carefully laid the sleeping baby down on the soft mattress. She didn’t wake up, and the teenagers were both satisfied with his efforts.

Finally, Dipper reached down and again lightly touched the baby’s forehead. He smiled once more at the subtle birthmark, faint but unmistakable. Five dots that perfectly replicated the constellation Cassiopeia.

“Goodnight, Cassie,” he murmured dreamily.

“We love ya, Baby Cass,” added Mabel in an adoring whisper.

The twins straightened up, verified the night light was on, and then took each other's hands and made their way out to the dining room to begin their homework.

* * *

> _This story was a long process for me. I’ve always been, and I remain, somewhat conflicted on the subject of “Pinecest progeny”. Nonetheless, this was a story I wanted to tell. I hope you liked it._
> 
> _Major thanks go out to my team of volunteer beta readers:Tumblr friends sevralships, sprucepinecest, stella-facem-ducens, yaschiri, pinetreeoverme, bizarrejoe, redtrot,, and especially the incredible work of my newest friend here on AO3, BR42. I can’t thank all of you enough._
> 
> _Also, thanks again to noneatnonedotcom on Tumblr for providing me with the prompt that, while unfulfilled, was the spark that ignited this fic._
> 
> _And obvious gratitude to pinestimes2 on tumblr for the incredible artwork. See **http://edward-or-ford.tumblr.com/post/147796397817/**  for the post dedicated to it._
> 
> _E-o-F_


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